JP2008312088

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DESCRIPTION JP2008312088
An object of the present invention is to provide a speaker capable of controlling the vibration of
the speaker even when the vibration of the speaker is small while suppressing the structure of
the device for detecting the vibration of the speaker from being complicated. SOLUTION: The
speaker 1 has an LED 21 joined to the side of the bobbin 14 in a direction in which the direction
of the emitted light crosses the direction in which the bobbin 14 vibrates, and the emission of the
light of the LED 21 so as to face the LED 21 The phototransistor 23 disposed on the direction
side and directly receiving the light emitted from the LED 21; and a shielding portion 22e
provided between the LED 21 and the phototransistor 23 for shielding the light emitted from the
LED 21. The vibration of the bobbin 14 changes the position of the LED 21, and the light amount
blocked by the shielding portion 22 e changes according to the position of the LED 21. [Selected
figure] Figure 4
スピーカ
[0001]
The present invention relates to a speaker, and more particularly to a speaker including a light
emitting element and a light receiving element for detecting vibration of the speaker.
[0002]
Conventionally, a speaker provided with a light emitting element and a light receiving element
for detecting the vibration of the speaker is known (see, for example, Patent Documents 1 to 4).
[0003]
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Patent Document 1 discloses a speaker in which a light emitting element is disposed on the side
of a voice coil such that an optical path of light emitted from the light emitting element is
perpendicular to a vibrating direction of the speaker.
In this speaker, a plurality of light receiving elements are arranged to face the light emitting
element, and the light receiving element receives light emitted from the light emitting element
vibrating with the voice coil, thereby detecting the amount of vibration displacement of the voice
coil. ing.
The vibration of the speaker is controlled based on the amount of vibration displacement of the
voice coil.
[0004]
Further, in Patent Document 2, the light emitting element is disposed at a portion where the
voice coil and the diaphragm are joined so that the optical path of the light emitted from the light
emitting element is perpendicular to the vibrating direction of the speaker. Speakers are
disclosed. In this speaker, a light detector (light receiving element) is disposed to face the light
emitting element, and the light detector receives light emitted from the light emitting element
that vibrates together with the voice coil and the diaphragm, and detects light. The displacement
of the voice coil and the diaphragm is determined by the position detection circuit connected to
the sensor. The light detector is configured to have a predetermined length in the direction in
which the voice coil and the diaphragm vibrate so that the center of the light emitting position of
the light emitting element can be captured even if the light emitting element vibrates. . The
vibration of the speaker is controlled based on the displacement of the voice coil and the
diaphragm.
[0005]
Further, according to Patent Document 3 described above, the photo reflector (one in which the
light emitting element and the light receiving element are contained in one case) is perpendicular
to the direction in which the light path of the light emitted from the photo reflector vibrates.
There is disclosed a loudspeaker arranged to be In this speaker, a pair of light reflecting portions
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are formed on the side portions of the bobbin at predetermined intervals in the direction in
which the bobbin vibrates. Also, in a state where the bobbin (speaker) does not vibrate, the
position of the photo reflector is such that the light emitted from the photo reflector strikes an
intermediate position between one light reflecting portion and the other light reflecting portion
on the side of the bobbin Is adjusted. When the vibration of the speaker is small, the light emitted
from the photo reflector does not strike the light reflection plate, and the light receiving element
housed in the photo reflector does not receive the light. On the other hand, when the speaker
vibrates to a predetermined width or more, light emitted from the photo reflector is reflected by
the light reflecting portion, so that the light is detected by the light receiving element. Thereby,
when the speaker vibrates beyond the predetermined width, the vibration of the speaker is
controlled.
[0006]
Further, according to Patent Document 4, a light emitting element for emitting light toward the
diaphragm, a lens provided between the light emitting element and the diaphragm, and light
emitted from the light emitting element and reflected by the diaphragm Discloses an optical
microphone provided with a light receiving element for receiving light. In this optical
microphone, the light receiving element is disposed on the side opposite to the light emitting side
of the light emitting element. In addition, the light receiving element includes an area for
detecting light at a position higher than the position where the light emitting element is disposed,
and an area for detecting light at a lower position. Further, below the light emitting element, a
shielding plate for blocking a part of light reflected by the diaphragm and received by the light
receiving element is provided. In this optical microphone, the light reflected by the diaphragm is
converged by the lens disposed between the diaphragm and the light emitting element, and the
focal point where the light is converged is moved by the vibration of the diaphragm. It is
configured to In addition, the position of the shielding plate is adjusted so as to have the case
where the upper or lower part of the reflected light is shielded by the shielding plate and the case
where the reflected light is not shielded by moving the focal point of the light. Thereby, when the
position of the diaphragm is changed, the reflected light detected in the area detecting the light
at a position higher than the position where the light emitting element of the light receiving
element is disposed and the area detecting the light at the lower position There is a difference in
the amount of light. The vibration of the diaphragm is detected from the difference between the
detected light amounts.
[0007]
Patent No. 2940587 JP-A-4-40199 JP-A-5-95597 JP-A-2001-238293
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[0008]
However, in the speaker described in Patent Document 1 described above, since a plurality of
light receiving elements for detecting light emitted from the light emitting element are required
to detect the amount of vibration displacement of the voice coil, vibration of the speaker can be
reduced. There is a problem that the structure of the device to be detected becomes complicated.
[0009]
Further, in the speaker described in Patent Document 2, the light detector has a predetermined
direction in which the voice coil and the diaphragm vibrate so that the center of the light
emitting position of the light emitting element can be captured even if the light emitting element
vibrates. By being configured to have a length, it may be considered necessary to arrange a
plurality of light receiving elements in the light detector.
This causes a problem that the structure of the device for detecting the vibration of the speaker
becomes complicated.
[0010]
In the speaker described in Patent Document 3, vibration of the speaker is controlled by
detecting light reflected by a pair of light reflecting portions formed at predetermined intervals in
the direction in which the bobbin vibrates. Therefore, when the vibration of the speaker is small,
there is a problem that the light emitted from the light emitting element is not reflected and the
vibration of the speaker can not be controlled.
[0011]
Further, in the optical microphone described in Patent Document 4 described above, light is
detected that is incident on a region that detects light at a position higher than the position
where the light emitting element of the light receiving element is disposed and a region that
detects light at a lower position. It is considered that it is necessary to arrange a plurality of light
receiving elements because it is configured to
This causes a problem that the structure of the device for detecting the position of the diaphragm
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is complicated.
[0012]
The present invention has been made to solve the above-described problems, and one object of
the present invention is to suppress the complication of the structure of a device for detecting
the vibration of the speaker and to prevent the vibration of the speaker To provide a speaker
capable of controlling the vibration of the speaker even when
Means for Solving the Problems and Effects of the Invention
[0013]
The speaker according to one aspect of the present invention includes a magnet, a bobbin around
which the coil is wound, and a direction in which emitted light crosses a direction in which the
bobbin vibrates. A light emitting element joined to the side of the bobbin, a light receiving
element disposed on the light emitting direction side of the light emitting element so as to face
the light emitting element, and directly receiving the light emitted from the light emitting
element A shield is provided between the light emitting element and the light emitting element,
and the position of the light emitting element is changed by the vibration of the bobbin, and the
light shielding element is interrupted by the position of the light emitting element. The light
quantity is configured to change.
[0014]
As described above, the speaker according to the one aspect includes the light emitting element,
the light receiving element, and the shielding portion provided between the light emitting
element and the light receiving element and configured to block light emitted from the light
emitting element. Since the light quantity intercepted by the shielding part is changed depending
on the position of the light emitting element, the position of the light emitting element can be
detected based on the light quantity received by the light receiving element. Can detect the
vibration of the bobbin (speaker).
In addition, unlike the case where the position of the light emitting element is detected by the
light emitting element and the plurality of light receiving elements arranged in the vibrating
direction of the light emitting element, one light receiving element for receiving the light quantity
of light emitted from the light emitting element Thus, the position of the light emitting element
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can be detected, so that the structure of the device for detecting the vibration of the speaker can
be prevented from becoming complicated.
In addition, the amount of light intercepted by the shielding unit changes depending on the
position of the light emitting element, and the amount of light intercepted by the shielding unit
changes regardless of the magnitude of the vibration of the bobbin. Even the vibration of the
bobbin can be detected.
[0015]
In the speaker according to the above aspect, preferably, the shielding portion is any one of the
lower half and the upper half of the light receiving portion when the light receiving portion for
receiving the light of the light receiving element is viewed from the emission direction side of the
light emitting element. It is arranged to cover the
According to this structure, for example, when the shielding portion is disposed to cover the
lower half of the light receiving portion, the light is not blocked by the shielding portion when
the light emitting element is at a higher position than the light receiving element. The amount of
light received by the light receiving element is increased, and when the light emitting element is
at a lower position than the light receiving element, the light is blocked by the shielding portion
to reduce the amount of light received by the light receiving element. Light intensity can be
changed.
[0016]
In the loudspeaker according to the aforementioned aspect, preferably, a support portion for
supporting the light receiving element is further provided, and the shielding portion is integrally
formed on the support portion. According to this structure, even when the shielding portion is
provided, the increase in the number of parts can be suppressed, and the structure can be
simplified as compared with the case where the shielding portion is formed of a member
different from the support portion.
[0017]
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In the speaker according to the aforementioned aspect, preferably, the light receiving element is
disposed so as to be located on the optical path of the light emitted from the light emitting
element when the bobbin is not vibrating. According to this structure, when the bobbin vibrates
easily by using the light receiving amount received by the light receiving element as a reference
when the bobbin is not vibrating, the light receiving amount as a reference and when the bobbin
vibrates The amount of vibration of the light emitting element (bobbin) can be detected from the
difference between the amount of light received and the amount of light received.
[0018]
In the speaker according to the above aspect, preferably, the light receiving element receives the
maximum light amount when the bobbin is positioned at one end of the vibration of the bobbin,
and the bobbin is positioned at the other end of the vibration of the bobbin Are arranged to
receive the minimum light quantity. According to this structure, the amount of light received by
the light receiving element changes according to the position of the bobbin, so that the vibration
of the bobbin can be detected from the amount of light received by the light receiving element.
[0019]
In the speaker according to the aforementioned aspect, preferably, the shielding portion is
disposed at a predetermined distance from the light receiving element and the light emitting
element in the emission direction. According to this structure, unlike the case where the shielding
portion is arranged to be in contact with the light receiving element, it is possible to suppress
that the portion in contact with the shielding portion of the light receiving element can not
receive light. It is possible to suppress the deterioration of the sensitivity.
[0020]
Hereinafter, an embodiment of the present invention will be described based on the drawings.
[0021]
FIG. 1 is a block diagram showing the overall configuration of a speaker device according to an
embodiment of the present invention.
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First, with reference to FIG. 1, an overall configuration of a speaker device 100 according to an
embodiment of the present invention will be described.
[0022]
A speaker device 100 according to an embodiment of the present invention is configured of a
speaker 1, a power amplifier 2, and an MFB (motional feedback) feedback amplifier 3. In
addition, an input signal (acoustic signal) is configured to be input to the MFB feedback amplifier
3. Further, the speaker 1 is provided with an LED 21 described later, and a phototransistor 23 is
provided at a position facing the LED 21. Further, the phototransistor 23 and the MFB feedback
amplifier 3 are electrically connected.
[0023]
2 to 4 are diagrams for explaining the structure of the loudspeaker according to the embodiment
of the present invention. FIG. 5 is a perspective view of a phototransistor support according to an
embodiment of the present invention. FIG. 6 is a diagram for explaining the amount of light
incident on the phototransistor according to the embodiment of the present invention. FIG. 7 is a
view of the shielding portion and the phototransistor according to an embodiment of the present
invention as viewed from the emission direction side of the LED. First, the structure of a
loudspeaker 1 according to an embodiment of the present invention will be described with
reference to FIGS. 1 to 7.
[0024]
In the speaker 1 according to one embodiment of the present invention, as shown in FIGS. 2 to 4,
the hollow conical cone paper 12 whose upper end is cut is placed with the cut surface facing
downward, inside the concave frame 11. It is arranged. Moreover, the side part of the flame ¦
frame 11 is provided with the hole 11a for the light radiate ¦ emitted from LED21 mentioned
later to pass. Further, the upper end of the frame 11 and the lower end of the cone paper 12 (the
end opposite to the cut upper end) are connected via the cone edge 13. In addition, a cylindrical
bobbin 14 is disposed below the corn paper 12, and a cut surface of the corn paper 12 whose
upper end is cut and the bobbin 14 are joined. Further, a convex cap portion 15 is joined to the
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upper surface of the bobbin 14 so as to cover the cut surface of the upper end of the cone paper
12 which has been cut. Further, between the inner side surface of the frame 11 and the side
portion of the bobbin 14, a damper 16 having a wavy cut surface is provided. The damper 16 is
provided so as to cover the space between the inner side surface of the frame 11 and the side
portion of the bobbin 14 in a plan view.
[0025]
Further, as shown in FIG. 4, the voice coil 17 is wound around the side of the bobbin 14. The
voice coil 17 is an example of the "coil" in the present invention. Further, a ring-shaped yoke 18
and a ring-shaped magnet 19 are disposed on the lower surface of the frame 11. The magnet 19
is an example of the "magnet" in the present invention. In addition, the magnet 19 is supported
by the yoke 20. Note that one side surface of the magnet 19 is disposed at a position facing the
voice coil 17. In addition, the magnet 19 is configured such that the other side surface of the
magnet 19 protrudes outside the side surfaces of the yokes 18 and 20. Further, at the central
portion of the yoke 20, a convex portion 20a to be fitted into the inner peripheral surface of the
cylindrical bobbin 14 is formed. Here, in the present embodiment, the LED 21 is joined to the
side portion of the bobbin 14 so that the direction of the emitted light intersects the direction in
which the bobbin 14 vibrates (the Z direction). The LED 21 is an example of the light emitting
element in the present invention.
[0026]
Further, as shown in FIGS. 2 to 4, the phototransistor support member 22 is fitted in a portion of
the ring-shaped magnet 19 which protrudes outside the side surfaces of the yokes 18 and 20.
The phototransistor support member 22 is an example of the support portion in the present
invention. Further, as shown in FIGS. 5 and 6, the phototransistor support member 22 is
configured by a pillar 22a, a phototransistor support 22b, a magnet attachment 22c, a tip 22d, a
shield 22e, and a protrusion 22f. .
[0027]
Further, in the present embodiment, as shown in FIGS. 5 and 6, the phototransistor support 22b
and the protrusion 22f are each flat and in a direction perpendicular to the direction in which the
column 22a extends. The phototransistor support member 22 is integrally formed. Further, in the
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present embodiment, the phototransistor 23 that directly receives the light emitted from the LED
21 is disposed between the upper surface of the phototransistor support 22b and the lower
surface of the protrusion 22f. The phototransistor 23 is an example of the light receiving
element in the present invention. Further, in the present embodiment, as shown in FIG. 4, the
phototransistor 23 is disposed on the light path of the light emitted from the LED 21 when the
bobbin 14 is not vibrating. Further, as shown in FIG. 1, the phototransistor 23 is electrically
connected to the MFB feedback amplifier 3.
[0028]
Further, in the present embodiment, as shown in FIGS. 4 to 6, the end of the phototransistor
support 22 b is positioned so that the shield 22 e of the phototransistor support 22 is located
between the phototransistor 23 and the LED 21. Provided in Further, the shielding portion 22e is
flat and is formed so as to be perpendicular to the direction in which the phototransistor support
portion 22b extends toward the LED 21 (with respect to the light path of the light emitted from
the LED 21). Further, in the present embodiment, the shielding portion 22 e is disposed at a
predetermined distance on the emission direction side of the phototransistor 23 and the LED 21.
Further, in the present embodiment, as shown in FIG. 7, the shielding portion 22 e of the
phototransistor supporting member 22 looks at the light receiving portion 23 a that receives the
light of the phototransistor 23 from the emission direction side of the LED 21. It is arranged to
cover the lower half.
[0029]
Further, as shown in FIG. 6, the end 221 f of the protrusion 22 f is a light receiving portion 23 a
of the phototransistor 23 so that the protrusion 22 f of the phototransistor support member 22
does not block light incident from above the phototransistor 23. It is formed so as not to project
beyond the front of the.
[0030]
Further, as shown in FIGS. 2 to 5, the magnet attachment portion 22 c of the phototransistor
support member 22 has a C shape, and the magnet attachment portion 22 c is closer to the side
surfaces of the yokes 18 and 20 of the magnet 19. It is fixed so as to be fitted into the outwardly
projecting portion.
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Incidentally, as shown in FIG. 5, the tip portion 22d of the phototransistor supporting member
22 is formed in a tapered shape so that the magnet mounting portion 22c can be easily fitted
into the magnet 19.
[0031]
Next, the operation of MFB (motional feedback) of the speaker 1 according to an embodiment of
the present invention will be described with reference to FIGS. 1, 4 and 6. FIG.
[0032]
As shown in FIG. 1, an input signal (sound signal) is input to the power amplifier 2 via the MFB
feedback amplifier 3.
The signal input to the power amplifier 2 is amplified by the power amplifier 2 and then input to
the speaker 1. The power amplifier 2 and the voice coil 17 are electrically connected, and as
shown in FIG. 4, the voice coil is operated by the current (input signal) flowing through the voice
coil 17 and the force acting between the magnet 19. The bobbin 14 on which 17 is wound
vibrates in the approximately ± 2 mm Z direction. Thereby, since the cone paper 12 vibrates, a
sound wave is emitted from the speaker 1.
[0033]
Next, when the bobbin 14 vibrates in the Z direction, as shown in FIG. 6, the LEDs 21 provided
on the side portions of the bobbin 14 also vibrate in the Z direction. Here, in the present
embodiment, the phototransistor 23 receives the maximum amount of light when the bobbin 14
is positioned at B which is one end of the amplitude of vibration of the bobbin 14, and the bobbin
14 is the other of the amplitude of vibration of the bobbin 14. It is arranged to receive the
minimum amount of light when it is located at the end C. The phototransistor 23 is arranged to
receive half of the maximum light quantity when the bobbin 14 is located at A, which is the
center of the amplitude of vibration of the bobbin 14. In addition, an electromotive force is
generated in the phototransistor 23 in accordance with the amount of incident light. This
electromotive force is input to the MFB feedback amplifier 3 (see FIG. 1) through the lead wire
24. By amplifying the input signal with the MFB feedback amplifier 3 based on the magnitude of
the electromotive force generated in the phototransistor 23, the vibration of the speaker 1 is
controlled such that the vibration of the bobbin 14 corresponds to the input signal.
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[0034]
In the present embodiment, as described above, the LED 21, the phototransistor 23, and the
shielding portion 22 e provided between the LED 21 and the phototransistor 23 for shielding the
light emitted from the LED 21 are provided. Since the position of the LED 21 can be detected
based on the amount of light received by the phototransistor 23 by changing the amount of light
blocked by the shielding portion 22e by this, the bobbin 14 to which the LED 21 is joined
(speaker The vibration of 1) can be detected. Also, unlike the case where the position of the LED
21 is detected by the LED 21 and the plurality of phototransistors 23 arranged in the vibrating
direction of the LED 21, the LED 21 is detected by one phototransistor 23 for receiving the light
quantity of light emitted from the LED 21. The position of the speaker can be detected, so that
the structure of the device for detecting the vibration of the speaker 1 can be prevented from
becoming complicated. Further, by configuring the amount of light blocked by the shielding
portion 22e to change depending on the position of the LED 21, the amount of light blocked by
the shielding portion 22e changes regardless of the magnitude of the vibration of the bobbin 14,
so the vibration of the bobbin 14 is small. In any case, the vibration of the bobbin 14 can be
detected.
[0035]
Further, in the present embodiment, the light shielding portion 22 e is disposed so as to cover
the lower half of the light receiving portion 23 a by viewing the light receiving portion 23 a that
receives the light of the phototransistor 23 from the emission direction side of the LED 21. When
the LED 21 is at a higher position than the phototransistor 23, the light is not blocked by the
shielding portion 22e, so that the amount of light received by the phototransistor 23 becomes
large, and when the LED 21 is at a lower position than the phototransistor 23, Since the amount
of light received by the phototransistor 23 is reduced by blocking the light, the amount of light
received by the phototransistor 23 can be changed according to the position of the LED 21.
[0036]
Further, in the present embodiment, the phototransistor supporting member 22 for supporting
the phototransistor 23 is provided, and the shielding portion 22e is integrally formed with the
phototransistor supporting member 22. Thus, even though the shielding portion 22e is provided,
the number of parts is reduced While suppressing the increase, the structure can be simplified as
compared with the case where the shielding portion 22e is formed of a member different from
the phototransistor supporting member 22.
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[0037]
Further, in the present embodiment, the phototransistor 23 is disposed so as to be positioned on
the optical path of the light emitted from the LED 21 in a state where the bobbin 14 is not
vibrating, so that the photo 14 is not By using the amount of light received by the transistor 23
as a reference, when the bobbin 14 easily vibrates, the difference between the amount of light
received as a reference and the amount of light received when the bobbin 14 vibrates The
amount of vibration can be detected.
[0038]
Further, in the present embodiment, when the phototransistor 23 is positioned at B (see FIG. 6),
which is one end of the amplitude of vibration of the bobbin 14, the phototransistor 23 receives
the maximum light quantity, and the bobbin 14 vibrates the bobbin 14. The light receiving
amount received by the phototransistor 23 changes according to the position of the bobbin 14
by arranging so as to receive the minimum light amount when positioned at C (see FIG. 6) which
is the other end of the amplitude of The vibration of the bobbin 14 can be detected from the
amount of received light 23.
[0039]
Further, in the present embodiment, the shielding portion 22e is disposed so as to be in contact
with the phototransistor 23 by arranging the shielding portion 22e at a predetermined distance
on the emission direction side of the phototransistor 23 and the LED 21. Differently, since it is
possible to suppress that the portion of the phototransistor 23 in contact with the shielding
portion 22e can not receive light, it is possible to suppress the deterioration of the sensitivity of
the phototransistor 23.
[0040]
It should be understood that the embodiments disclosed herein are illustrative and nonrestrictive in every respect.
The scope of the present invention is indicated not by the description of the embodiments
described above but by the claims, and further includes all modifications within the meaning and
scope equivalent to the claims.
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[0041]
For example, in the embodiment described above, the shield 22e is disposed to cover the lower
half of the light receiver 23a when the light receiver 23a for receiving the light of the
phototransistor 23 is viewed from the emission direction of the LED 21. However, the present
invention is not limited to this, and the shielding portion 22e may be disposed to cover the upper
half of the light receiving portion 23a.
[0042]
Moreover, although the example which uses LED21 as a light emitting element was shown in the
said embodiment, this invention may use not only this but light emitting elements other than
LED21.
[0043]
FIG. 1 is a block diagram showing an overall configuration of a speaker device according to an
embodiment of the present invention.
FIG. 1 is a perspective view of a loudspeaker according to an embodiment of the present
invention.
FIG. 1 is a side view of a speaker according to an embodiment of the present invention.
It is sectional drawing along the 200-200 line of FIG.
FIG. 5 is a perspective view of a phototransistor support member according to an embodiment of
the present invention.
It is a figure for demonstrating the light quantity which injects into the phototransistor by one
Embodiment of this invention.
It is the figure which looked at the shielding part by one Embodiment of this invention, and the
phototransistor from the radiation ¦ emission direction side of LED.
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Explanation of sign
[0044]
DESCRIPTION OF SYMBOLS 1 Speaker 14 Bobbin 17 Voice coil (coil) 19 Magnet (magnet) 21
LED (light emitting element) 22 Phototransistor support member (support part) 22e Shielding
part 23 Phototransistor (light receiving element) 23a Light receiving part
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