JP2005184393A - Acoustic reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acoustic reproducing apparatus improving sound pressure in a high frequency band. <P>SOLUTION: An air layer Q is formed as a closed space between an exciting plate 2 and a panel 20 as a sound emitting member. An exciting means 3 vibrates the exciting plate 2, and the vibration of the exciting plate 2 is applied to the panel 20 through the air layer Q. Since the exciting plate 2 is vibrated following the driving level of the exciting means 3, the vibration of relatively high frequency of the exciting plate 2 is applied to the panel 20 as the sound pressure of the air layer Q, and the sound with high level of treble band is outputted from the panel 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sound reproducing device that generates sound by vibrating a sound generating member such as a transparent panel of a display unit or a housing of an electronic device, and particularly relates to a sound reproducing device that can generate sound in a high frequency region with high sound pressure.

In the speaker described in Patent Document 1, a plurality of vibration generators are provided on the back side of a panel in which a large first diaphragm is supported on the front surface. In each vibration generator, a small second diaphragm is supported on a frame on which driving means having a magnet and a voice coil is mounted. Further, the frame and the panel are fixed through a vent hole, and a closed space is formed between the first diaphragm and the second diaphragm. When the driving means is driven, the vibration from the second diaphragm is transmitted to the first diaphragm via the closed space, and the first diaphragm generates a sound.
JP 2003-158787 A

  The small speaker provided with the sheet-like diaphragm described in Patent Document 1 can vibrate the diaphragm by following the drive level of the driving means by making the diaphragm soft. However, if the panel is enlarged and the diaphragm provided on the panel becomes large and rigid, it becomes difficult to cause the diaphragm to vibrate at a high frequency by following the drive level of the driving means, and the vicinity of 10,000 Hz (Hz). The sound in the high frequency band cannot be output with high sound pressure. As described above, the sound pressure level in the high frequency region decreases or disappears, which causes the sound quality level to deteriorate. Therefore, in the case where a highly rigid diaphragm is provided, a large drive means is required or a plurality of drive means are required.

  Also, if the diaphragm provided on the large panel is thin and soft, it will be too soft to be placed on the surface of the device, and the vibration propagation characteristics will be poor, so it will not be possible to secure output at high sound pressure. .

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a sound reproducing apparatus capable of outputting a high sound pressure particularly in a high frequency band.

The present invention relates to a sound reproducing device provided with a sound generating member and an excitation means for causing the sound generating member to vibrate and generate sound.
A diaphragm is opposed to the sounding member, a closed space is interposed between the sounding member and the diaphragm, and sounding vibration is transmitted from the excitation means to the diaphragm. To do.

  In the sound reproducing device of the present invention, the diaphragm is opposed to the sound producing member through the closed space, and the vibration of the diaphragm can be transmitted to the sound producing member through the air vibration in the space. Therefore, the sounding member can be vibrated in a wide frequency band, and particularly when the diaphragm is vibrated at a high frequency, it is possible to generate a large amplitude to the sounding member through the air vibration. The output in the high sound range can be increased.

  For example, in the present invention, the diaphragm is fixed to the sound generation member via a frame-shaped spacer, and the closed space is formed by being surrounded by the sound generation member, the vibration plate, and the spacer. Has been.

  The diaphragm is preferably formed of a synthetic resin plate or film. Further, the spacer is preferably an adhesive layer, and can be composed of, for example, a double-sided tape having adhesive members formed on both sides. When the diaphragm is formed of a resin film, the resonance frequency of the diaphragm is lowered and sound can be generated in a wide band.

  Further, the closed space may be partially opened. In this case, the open portion may be formed on the spacer or may be formed on the diaphragm.

  Moreover, it is preferable that the resonance frequency of the diaphragm is set lower than the resonance frequency of the sound generating member. For example, the diaphragm and the sounding member may be a combination of the same material or a combination of different materials. In the case of a combination of the same kind of materials, it is preferable that the thickness dimension of the diaphragm is formed thinner than the thickness dimension of the sound generating member.

  The sound generating member may be a rectangular or square panel, and the excitation means may be disposed in the vicinity of the side edge of the panel.

  As described above, the excitation means is arranged in the vicinity of the side edge of the panel, so that the central portion of the panel can be used as a display screen or the like.

  The present invention can improve the sound pressure in the high frequency band by causing the diaphragm to vibrate following the drive level of the excitation means and transmitting the vibration to the sound producing member through the closed space.

  FIG. 1 is a plan view of an electronic apparatus equipped with a sound reproduction device according to a first embodiment of the present invention as viewed from the sound generation side, FIG. 2 is an exploded perspective view of the sound reproduction device, and FIG. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1, and FIG. 6 is a graph showing a comparison of sound frequency band characteristics between the first embodiment and the comparative example. .

  FIG. 1 shows an electronic device 10 on which a sound reproducing device of the present invention is mounted, and a transparent synthetic resin panel 20 is provided on the front surface of a housing 21. In this embodiment, the panel 20 functions as a sounding member. On the back side of the panel 20, the sound reproducing devices 1 and 1 are disposed inside the left and right (X1-X2 direction) side edges of the panel. An intermediate portion between the left and right sound reproducing apparatuses 1 and 1 is a display see-through region, and an FPD (flat display unit) 30 having a shape indicated by a two-dot chain line in FIG.

  The sound reproducing device 1 and the sound reproducing device 1 located on both the left and right sides have the same configuration. In the following description, the X direction is the horizontal direction and the Y direction is the vertical direction. The panel 20 has a rectangular shape in which the horizontal dimension is longer than the vertical dimension.

  As shown in FIG. 2, the sound reproducing device 1 has excitation means 3. The excitation means 3 is disposed in parallel with the side edges of the panel 20 in the vicinity of both side edges of the panel 20.

  The excitation means 3 is configured by connecting an excitation plate 2 and a support member 5. The excitation plate 2 has an elongated thin plate shape in which the length dimension in the vertical direction (Y direction) is sufficiently larger than the width dimension in the horizontal direction (X direction). The excitation plate 2 is formed of a synthetic resin plate material such as polycarbonate, acrylic, or polyethylene terephthalate (PET). The excitation plate 2 is preferably formed to be particularly thin, and is not limited to a synthetic resin and may be a thin metal plate.

  The support member 5 is formed of a magnetic material such as a steel plate, and is formed with connecting portions 5a and 5a bent in an L shape at both ends in the vertical direction, and on both side portions extending in the vertical direction. Bent portions 5b and 5b are formed. The vertical dimension of the support member 5 and the vertical dimension of the excitation plate 2 are formed substantially the same, and the connecting portions 5a and 5a of the support member 5 are attached to both ends of the excitation plate 2 with an adhesive or the like. It is fixed with. As shown in FIGS. 3 and 4, the bent portions 5 b and 5 b of the support member 5 are set to dimensions that do not contact the excitation plate 2.

  The bending rigidity of the excitation plate 2 is sufficiently smaller than the bending rigidity of the support member 5. The resonance frequency of the excitation plate 2 is sufficiently smaller than the resonance frequency of the panel 20, for example, the resonance frequency of the panel 20 is 1 kHz or more and 3 kHz or less, and the resonance frequency of the excitation plate 2 is 200 Hz or more and 600 Hz or less. .

  As shown in FIG. 3, a magnet M formed of a permanent magnet such as ferrite or rare earth as a magnetic field generating means is fixed to the support member 5 at the bottom 5c facing the excitation plate 2. The magnet M has an elongated shape in the vertical direction and is fixed to the central portion of the support member 5 in the vertical direction. A yoke 6 made of a magnetic material is overlapped and fixed to the magnet M. The yoke 6 is formed with the same area as the upper surface of the magnet M, and when the yoke 6 and the magnet M are overlapped with each other as shown in FIGS. Each is formed with a thickness dimension that does not contact.

  On the other hand, the excitation plate 2 is provided with a coil C on the side facing the support member 5. The coil C is wound in a rectangular frame shape with a coated copper wire or the like and is elongated in the vertical direction, and is fixed to the longitudinal center of the excitation plate 2 with an adhesive or the like. The coil C has a pair of vertical current paths Ca and ca extending in the vertical direction and a pair of horizontal current paths Cb and Cb extending in the horizontal direction.

  When the support member 5 is fixed to the excitation plate 2 via the connecting portions 5a, 5a, the entire yoke 6 and a part of the magnet M are inserted so as to be located inside the coil C. . At this time, gaps G and G having minute intervals are formed between the bent portions 5b and 5b of the support member 5 and the magnet M and the yoke 6, and the longitudinal current of the coil C is formed in the gaps G and G. Roads Ca and Ca are located. That is, the bent portions 5b and 5b function as opposing yokes.

  For example, as shown in FIG. 3, in the magnet M in which the Z1 side is magnetized to the N pole and the Z2 side is magnetized to the S pole, the N pole of the magnet M, the yoke 6, the gap G, and the bent portion 5b of the support member 5 A magnetic path passing through the bottom 5c and the south pole of the magnet M is formed. At this time, as shown in FIG. 3, by energizing the longitudinal current path Ca on the X1 side of the coil C toward the back side of the paper, the current in the opposite direction to the current path on the opposite X2 side current path Ca is obtained. Therefore, the support member 5 is subjected to a force to bend and deform in the Z2 direction. In addition, by energizing in the direction opposite to the above, a force to bend and deform in the Z1 direction acts on the support member 5. Thus, by vibrating the support member 5 in the Z1-Z2 direction, the excitation plate 2 also vibrates in the Z1-Z2 direction at the same time.

  The excitation means 3 is not only a drive means using magnetism, but also a piezoelectric vibrator is provided between the excitation plate 2 and the support member 5, and this piezoelectric vibrator is attached to the excitation plate 2 and the support member 5. It may be bonded and the excitation plate 2 may be deformed by vibration. Further, a magnet and a yoke may be provided on the excitation plate 2 side, and a coil may be provided on the support member 5 side.

  Further, a pair of upright pieces are formed on the bottom 5c of the support member 5, and the upright pieces are arranged so as to be located outside the lateral current paths Cb and Cb of the coil C, and the upright pieces and A magnetic path may be formed by the yoke 6, the magnet M, and the bottom portion 5c.

  In the excitation means 3 in this embodiment, when the coil C is energized, a vibration force acts on both the excitation plate 2 and the support member 5 so that the excitation plate 2 and the support member 5 approach each other. They vibrate away from each other. That is, the excitation means 3 has an excitation function independently. Since the excitation plate 2 has low bending rigidity and both ends extending in the vertical direction are connected to the connection portions 5a and 5a of the support member 5, the excitation plate 2 uses the fixed portions at the connection portions 5a and 5a as simple support portions. Oscillate with its center bent. The support member 5 also vibrates, but its amplitude is sufficiently smaller than the amplitude of the excitation plate 2.

  Since the excitation plate 2 is formed with an area smaller than the area of the panel 20, when the coil C of the excitation means 3 is energized, vibration based on the energization level, that is, the energization amount and energization direction of the coil C. Is easily applied to the excitation plate 2.

  In the sound reproducing device 1 of the present embodiment, the transmission member 4, the diaphragm 8a, and the spacer 8b are provided between the excitation plate 2 and the panel 20 as the sounding member. The diaphragm 8a has a rectangular shape smaller than the panel 20 and the excitation plate 2 and faces the panel 20 in parallel. The entire circumference of the long side and the short side of the diaphragm 8a is fixed to the panel 20 via the frame-like spacer 8b. As a result, a substantially completely sealed and closed space surrounded by the panel 20, the diaphragm 8a and the spacer 8b is formed, and the air layer Q is provided in this space.

  The diaphragm 8a is formed of a synthetic resin material such as polycarbonate, acrylic, and PET, and is formed in a film shape that is thinner than the panel 20 and is formed to be the same as or thinner than the excitation plate 2. The diaphragm 8a may be formed of a thin metal plate such as a leaf spring material. The resonance frequency of the diaphragm 8 a itself is lower than the resonance frequency of the panel 20. The resonance frequency of the diaphragm 8a itself is equal to or less than the resonance frequency of the excitation plate 2, and is, for example, 100 Hz or more and 600 Hz or less.

  The spacer 8b is an adhesive layer formed of a double-sided tape or the like formed in a square frame shape with a minute thickness. The closed space is not limited to an air layer, but may be an air layer filled with other gas, or a liquid layer.

  The air layer Q does not need to be a completely closed space, and the spacer 8b may be partially formed with a through hole communicating with the outside. Such a through hole is not limited to the spacer 8b, and may be formed on the excitation plate 2 side or the panel 20 side.

  A part of the excitation plate 2 of the excitation means 3 is indirectly supported by the panel 20. That is, the excitation plate 2 is supported by the panel 20 through the transmission member 4 and the air layer Q at the intermediate portion between the connecting portion 5a and the connecting portion 5a. The transmission member 4 is made of the same synthetic resin as described above, and has dimensions in the vertical direction and the horizontal direction that are shorter than the vibration plate 8a, respectively, and the vibration plate 8a and the vertical center portion of the transmission member 4 and the excitation plate. Bonding is performed so that the vertical central portion of the two coincides.

  As shown in FIG. 2, the longitudinal direction (Y direction) of the excitation plate 2 has an elongated shape longer than the width direction in the lateral direction (X direction), and the excitation plate 2 extends in the Z direction. The shape has a sufficiently smaller area than the facing vibration surface 2a. That is, the transmission member 4 is formed such that the longitudinal dimension is longer than the longitudinal dimension of the magnet M and the yoke 6 and the lateral dimension is shorter than the width dimension of the excitation plate 2. The excitation plate 2 is fixed to the longitudinal central portion with an adhesive or the like. Thus, the transmission member 4 is fixed to a part of the vibration surface 2 a of the excitation plate 2, and the non-connecting portion 2 b where the transmission member 4 is not fixed on both sides in the Y direction of the transmission member 4. , 2b are formed.

  As shown in FIG. 1, the sound reproducing apparatus 1 of the present embodiment is arranged in the same manner at the edge of the panel 20 on the short side in the X1 direction. The panel 20 is provided in an opening 23 formed in the casing 21 formed by a bottom plate 21a and a side plate 21b as shown in FIGS. The side plate 21b of the housing 21 is formed with a support portion 21c projecting inward over the entire inner wall. A damper 22 is fixed to the support portion 21c, and the peripheral portion of the panel 20 is supported on the bumper 22 in an elastic state.

Next, the operation of the sound reproducing device 1 of the present invention will be described.
In this sound reproducing apparatus 1, when the coil C is energized based on an audio signal or a music signal, the support member 5 generates self-vibration in the Z1-Z2 direction by the excitation means 3, and in particular, the excitation plate 2 is It is vibrated in the Z1-Z2 direction.

  Since the excitation plate 2 is formed with an area smaller than that of the panel 20, the response to the input voltage (input current) level is improved. Since the excitation plate 2 is fixed through the transmission member 4 only at the central portion, the vibrations at the unconnected portions 2b and 2b at both end portions in the Y direction of the excitation plate 2 not fixed to the panel 20 are Amplified by the vibration operation of the support member 5, the excitation plate 2 is vibrated with a large amplitude.

  The vibration of the excitation plate 2 having such a large amplitude acts on the central portion of the vibration plate 8a via the transmission member 4, and the vibration plate 8a is forcibly vibrated. The vibration of the diaphragm 8a is transmitted to the panel 20 through the spacer 8b. Further, the vibration of the diaphragm 8a forms an air density in the air layer Q, and the sound pressure of the air layer Q is applied to the panel 20. Given.

  Since the resonance frequency of the diaphragm 8a is low, the diaphragm 8a vibrates with a large amplitude in a wide frequency band. At this time, a relatively low frequency is applied to the panel 20 through the spacer 8b, but vibration in a high frequency band is effectively applied to the panel 20 from the diaphragm 8a through the air layer Q. Therefore, a large output sound can be obtained from the panel 20 even in a high frequency band. Further, stereo sound can be generated by the left and right sound reproducing apparatuses 1 and 1.

FIG. 5 is a cross-sectional view showing the sound reproducing device 30 according to the second embodiment of the present invention.
In this sound reproducing device 30, the excitation plate 2 of the excitation means 3 functions as a vibration plate that applies sound pressure to the air layer Q1, and the excitation plate 2 is attached to the panel 20 as a sounding member via a spacer 31. An air layer Q1 that is directly fixed and sealed in a space surrounded by the panel 20, the excitation plate 2, and the spacer 31 is formed. Other configurations are the same as those of the sound reproducing device 10 of the first embodiment.

  The spacer 31 shown in FIG. 5 is also formed in a square frame shape with a constant thickness as in the spacer 8b, and one surface side of the spacer 31 is fixed to the entire peripheral edge of the excitation plate 2, and the other surface side is a panel. 20 is fixed.

  Also in the sound reproducing device 30 shown in FIG. 5, when the coil C of the excitation means 3 is energized, the excitation plate 2 having a low resonance frequency can be vibrated with a large amplitude in a wide band, and the vibration is transmitted through the spacer 31. While being given to the panel 20, the panel 20 is driven by giving sound pressure to the air layer Q1. Therefore, it is possible to obtain a high frequency sound with a wide frequency band.

  FIG. 6 is a graph comparing the relationship between frequency (hertz) and sound pressure level (decibel). The solid line shown in FIG. 6 is the case where the sound reproducing device 30 of the embodiment shown in FIG. 5 is driven, and the dotted line shown in FIG. 6 is the connecting portion 5a at both ends of the support member 5 without providing the excitation plate 2. , 5a is fixed to the panel 20 directly.

  As shown in the portion surrounded by the dotted line in FIG. 6, in the comparative example, the sound pressure in the high frequency band near 10 kHz (after 6 kHz) is lowered. This is because the excitation means 3 is small with respect to the panel 20, and therefore the panel 20 cannot be vibrated following the current level applied to the coil C when the panel 20 has high rigidity.

  On the other hand, as shown in the present embodiment, the excitation plate 2 is provided, and the excitation plate 2 is supported by the panel 20 via the air layer Q1, thereby following the current level applied to the coil C by the excitation plate 2. Therefore, the sound pressure in the high frequency band can be improved with respect to the panel 20.

  In the sound reproducing device 1 according to the present invention, the panel 20 is made transparent, and an FPD formed of liquid crystal or the like is arranged in the center of the panel 20, so that the sound reproducing device 1 is arranged based on the screen displayed on the FPD. The sound may be generated from the panel 20 by driving.

  Further, the sound generating member on which the sound reproducing device 1 is mounted is not limited to the panel 20 described above, and a vibrable member disposed inside the casing of the electronic device or the casing of the electronic device itself. Can be used as a sounding member.

  In the transmission member 4 and the diaphragm 8a as other members of the present embodiment, the transmission member 4 may be integrally formed on the excitation plate 2 side.

The top view which shows the electronic device by which the sound reproduction apparatus of embodiment of this invention is mounted, An exploded perspective view of the sound reproducing device, FIG. 3 is a sectional view taken along line 3-3 in FIG. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. Sectional drawing which shows the sound reproduction apparatus of the 2nd Embodiment of this invention, A graph showing the characteristics of the frequency band,

Explanation of symbols

C Coil M Magnet Q, Q1 Air layer 1 Sound reproducing device 2 Excitation plate 2a Vibration surface 3 Excitation means 4 Transmission member 5 Support member 5a Connection portion 5b Bending portion 6 Yoke 8a Vibration plate 8b, 31 Spacer 10 Electronic device 20 Panel 21 Housing 22 Damper 30 FPD

Claims (7)

In a sound reproducing device provided with a sound generating member and an excitation means for applying vibration to the sound generating member to generate sound,
A diaphragm is opposed to the sounding member, a closed space is interposed between the sounding member and the diaphragm, and sounding vibration is transmitted from the excitation means to the diaphragm. Sound reproducing device.   2. The diaphragm is fixed to the sound generation member via a frame-shaped spacer, and the closed space is formed by being surrounded by the sound generation member, the vibration plate, and the spacer. The sound reproducing device described.   The sound reproducing device according to claim 2, wherein the diaphragm is made of a synthetic resin.   The sound reproducing device according to claim 2, wherein the spacer is an adhesive layer.   The sound reproducing device according to claim 1, wherein the closed space is partially opened.   The sound reproducing device according to claim 1, wherein a resonance frequency of the diaphragm is set lower than a resonance frequency of the sound producing member.   The sound reproducing device according to claim 1, wherein the sound generating member is a rectangular or square panel, and the diaphragm is disposed in the vicinity of a side edge of the panel.

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