JP2004364269A - Sound reproduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound reproducing device capable of giving a user a feeling of sound being reproduced from a display means and reproducing sound with high quality.
SOLUTION: The present invention is a sound reproducing device provided with a display means, a substrate, a vibration panel, and at least one electro-acoustic transducer. The display means displays an image on the display surface. The substrate forms a first space between the substrate and the display surface of the display means, and is made of a material that transmits visible light. The vibrating panel is disposed on the opposite side of the substrate with respect to the display device, forms a second space between the vibrating panel and the substrate, and is made of a material that transmits visible light. The electro-acoustic transducer emits sound to the second space.
[Selection diagram] Fig. 1

Description

  The present invention relates to a sound reproducing apparatus, and more particularly, to a sound reproducing apparatus having a display means and acoustically driving a transparent vibration panel.

  2. Description of the Related Art Conventionally, an audio reproducing apparatus that reproduces sound from a display screen has been considered. For example, there is a sound reproducing device that emits sound by vibrating a transparent vibrating panel provided on a front surface of a display screen (for example, see Patent Document 1). Hereinafter, this sound reproducing apparatus will be described with reference to FIG.

  FIG. 11 is an external perspective view of a television set provided with a conventional sound reproducing device. In FIG. 11, the television set includes a cabinet 1, a cathode ray tube 2, a front panel 3, a driver 4, and an acoustic slit 5. The front panel 3 is attached to the front of the cathode ray tube 2. The front panel 3 is made of a material having a high light transmittance, such as glass or transparent acryl. The driver 4 is an electromagnetic speaker and is directly connected to the back of the front panel 3. A plurality of acoustic slits 5 are provided (four in FIG. 11), and are provided on the outer periphery of the cathode ray tube 2. The television set shown in FIG. 11 reproduces sound by a method in which a transparent vibration panel is directly driven by a driver.

  The operation of the sound reproducing device shown in FIG. 11 will be described. When an electric signal is applied to the driver 4, the driver 4 vibrates. Since the driver 4 is directly attached to the front panel 3, the vibration of the driver 4 is mechanically transmitted to the front panel 3, so that the front panel 3 vibrates. That is, if the electric signal applied to the driver 4 is a sound signal, the sound is reproduced from the front panel 3 attached to the front surface of the cathode ray tube 2. Further, since the front panel 3 is made of a material having a high light transmittance, the front panel 3 does not disturb the image reproduced by the CRT 2. Therefore, simultaneous reproduction of video and sound is possible with the television set shown in FIG.

  When the volume of the space between the front panel 3 and the cathode ray tube 2 is small, the air pressure in the space increases, and there is a problem that the reproduction limit of a low-frequency range in sound reproduction increases. The acoustic slit 5 is provided for the purpose of preventing this problem. Since the back sound of the front panel 3 passes through the acoustic slit 5 and is radiated into the cabinet 1, the acoustic slit 5 does not increase the air pressure in the space.

  Although the sound reproducing device shown in FIG. 11 is used for a television set, there is also a sound reproducing device used for a mobile phone (for example, see Patent Document 2). This sound reproducing device reproduces sound by vibrating the outer case by a driver directly attached to the outer case of the mobile phone. Hereinafter, this sound reproducing apparatus will be described with reference to FIG.

  FIG. 12 is an external view of a mobile phone provided with a conventional sound reproducing device. 12, the mobile phone includes an outer case 10, an antenna 11, a sound board 12, a driver 13, and a display screen 14. The sound board 12 is arranged on the upper front surface of the outer case 10 and is formed so that the outer peripheral portion thereof is thin, though not shown. The driver 13 is directly attached to the back side of the sound board 12. The display screen 14 is provided on the front surface of the outer case 10 and below the sound board 12.

The operation of the sound reproducing device shown in FIG. 12 will be described. When an electric signal is applied to the driver 13, the vibration of the driver 13 is directly transmitted to the sound board 12 formed on the outer case 10. As a result, sound is reproduced by the sound board 12 vibrating.
Japanese Patent No. 20221497 JP-A-8-275293

  In the sound reproducing device shown in FIG. 11, the driver 4 needs to be attached so as not to obstruct the display screen of the cathode ray tube 2, and is therefore attached near the end of the front panel 3. However, in a sound reproducing apparatus that employs a method in which the front panel 3 is directly driven by the driver 4, if the driver 4 is mounted near the end of the front panel 3, the sound quality of reproduced sound will be degraded.

  Further, since the front panel 3 has a role as a vibration panel that radiates sound and a role as a protection panel that protects the cathode ray tube 2, a moderate strength is required. Therefore, the front panel 3 needs to be configured to be somewhat thick. For this reason, the weight of the front panel 3 increases, so that the vibration of the front panel 3 by the driver 4 decreases, and the reproduction sound pressure decreases. Therefore, in the sound reproducing device shown in FIG. 11, the efficiency of the reproduced sound pressure with respect to the driver is very low as compared with a normal speaker.

  On the other hand, the sound reproducing device shown in FIG. 12 cannot be applied to a recent mobile phone which requires a large display screen. Specifically, in the sound reproducing device shown in FIG. 12, the display screen 14 and the sound board 12 are arranged at different positions, so that the sound board 12 is in the way and the enlargement of the display screen 14 is limited. . Furthermore, since the position of the display screen 14 and the position where the sound is reproduced are different, the user cannot feel as if the sound is being reproduced from the display screen 14.

  SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sound reproducing apparatus which gives a user a feeling that sound is being reproduced from a display means and is capable of reproducing with high sound quality.

In order to solve the above problems, the present invention has the following configurations.
That is, the present invention is a sound reproducing device including a display unit, a substrate, a vibration panel, and at least one electro-acoustic transducer. The display means displays an image on the display surface. The display means is a concept including, for example, a picture or a picture on which an image is drawn, in addition to a display device such as a liquid crystal display device. The substrate forms a first space between the substrate and the display surface of the display means, and is made of a material that transmits visible light. The vibrating panel is arranged on the opposite side of the substrate with respect to the display means, forms a second space between the vibrating panel and the substrate, and is made of a material that transmits visible light. The electro-acoustic transducer emits sound into the second space.

  Note that typically, a sound hole is provided in the substrate, and the electroacoustic transducer emits sound to the second space through the sound hole.

  Further, the sound reproducing device may further include a case having an opening covered by the vibration panel. The case includes a substrate, display means, and an electro-acoustic transducer therein.

  Further, the vibration panel may be configured by a touch panel.

  Further, the sound reproducing device may further include an antenna for receiving a signal, and signal processing means. The signal processing means performs predetermined signal processing on the signal received by the antenna, and inputs the signal subjected to the signal processing to the electroacoustic transducer.

  Further, the sound reproducing device may include two electroacoustic transducers. At this time, if the signal received by the antenna includes a signal indicating the reception sound, the signal processing unit inputs the signal to one of the electroacoustic transducers, and outputs the reception sound to the signal received by the antenna. When a signal other than the signal indicating is included, the signal is input to the other electroacoustic transducer.

  According to the invention, the vibrating panel is acoustically driven by sound emitted from the electro-acoustic transducer into the second space. When the vibration panel is acoustically driven in this manner, the mounting position of the electroacoustic transducer does not affect sound reproduction. Therefore, the sound quality does not deteriorate due to the mounting position of the electroacoustic transducer. Further, since the electro-acoustic transducer can be freely arranged, the electro-acoustic transducer does not interfere with the display means, and the user can feel as if the sound is being reproduced from the display means.

(Embodiment 1)
First, an audio reproducing device according to Embodiment 1 of the present invention will be described using FIG. 1 and FIG. FIG. 1 is a diagram showing a configuration of the sound reproduction device according to the first embodiment. FIG. 1A is a plan view of the sound reproducing device, and FIG. 1B is a cross-sectional view taken along a line AB of the sound reproducing device. The sound reproduction device according to the first embodiment is a form realized as a portable terminal device such as a mobile phone or a PDA.

  In FIG. 1, the sound reproducing device includes an outer case 20, a display device 21, a substrate 22, a vibration panel 23, a spacer 24, and an electroacoustic transducer 26. The display device 21 is, for example, a liquid crystal display device. The substrate 22 and the vibration panel 23 are made of a material that transmits visible light. The substrate 22 is made of, for example, glass or acrylic resin. The vibration panel 23 is made of, for example, acrylic resin or PET (polyethylene terephthalate).

  In FIG. 1, the outer case 20 has an opening having substantially the same size as the display device 21, and the display device 21 is installed so as to cover the opening. That is, the periphery of the display device 21 is connected to the opening. The display device 21 is arranged inside the outer case 20. The substrate 22 is disposed outside the display device 21 with respect to the outer case 20 (left side in FIG. 1). A first space is formed between the display device 21 and the substrate 22. The peripheral part of the substrate 22 is connected to the outer case 20. The vibration panel 23 is disposed outside the substrate 22 with respect to the outer case 20 (left side in FIG. 1). That is, the vibration panel 23 is disposed to face the display device 21 with respect to the substrate 22. The substrate 22 and the vibration panel 23 are fixed to each other at their peripheral portions by spacers 24. Thus, a second space is formed between the substrate 22 and the vibration panel 23. The board 22 and the outer case 20 are provided with sound holes 27. The electroacoustic transducer 26 is disposed on the opposite side of the substrate 22 from the second space 25. The electroacoustic transducer 26 is connected to the outer case 20 so as to cover the sound hole 27. In another embodiment, the electroacoustic transducer 26 may be directly connected to the substrate 22. In addition, the electroacoustic transducer 26 is disposed inside the outer case 20, similarly to the display device 21.

  FIG. 2 is a sectional view of the electroacoustic transducer 26 shown in FIG. 2, the electroacoustic transducer 26 includes a pot-shaped yoke 40, a magnet 41, a plate 42, a voice coil 44, a diaphragm 45, and a frame 46. The frame 46 is connected to the outer case 20 on the outer periphery of the sound hole 27 so as to cover the sound hole 27. The yoke 40 has an outer lower surface (the right surface in FIG. 2) fixed to the center of the frame 46. The magnet 41 is provided at the center of the yoke 40. The plate 42 is disposed on the upper surface of the magnet 41. The yoke 40 and the plate 42 are arranged such that a magnetic gap 43 is formed between the inner peripheral surface of the yoke 40 and the outer peripheral surface of the plate 42. Further, the outer periphery of the diaphragm 45 is fixed to the frame 46. The voice coil 44 is fixed to the diaphragm 45 so as to be inserted into the magnetic gap 43.

  The operation of the sound reproducing device configured as shown in FIGS. 1 and 2 will be described. When an electric signal is applied to the voice coil 44 inserted in the magnetic gap 43 of the electroacoustic transducer 26, a driving force is generated in the voice coil 44. A sound is generated by vibrating the diaphragm 45 coupled to the voice coil 44 by the driving force. The sound radiated from the diaphragm 45 propagates from the sound hole 27 to the second space 25. As a result, the vibration panel 23 vibrates at the sound pressure of the second space 25. That is, the vibration panel 23 is acoustically driven and vibrates. As a result, sound is emitted from the vibration panel 23. As described above, when the vibration panel 23 is acoustically driven, sound is propagated through the second space, so that the mounting position of the electroacoustic transducer 26 as a driver affects the sound quality of reproduced sound. Do not give. Therefore, the mounting position of the electroacoustic transducer 26 can be freely designed, and a decrease in the sound quality of the reproduced sound can be prevented.

  When the outer peripheral portion of the vibration panel 23 is fixed by the spacer 24, the vibration panel 23 vibrates so that the vibration panel 23 itself is bent. When the spacer 24 is formed of a suspension made of an elastic body, the vibration panel 23 itself vibrates so as to perform a piston motion. In the present invention, the vibration panel 23 may vibrate so that the vibration panel 23 itself bends, or may vibrate so that the vibration panel 23 itself performs a piston motion.

  When the vibration panel 23 vibrates due to the sound pressure of the sound radiated to the second space 25, the same sound pressure is applied to the substrate 22 as the vibration panel 23. Therefore, a force for vibrating the substrate 22 acts on the sound pressure, similarly to the vibration panel 23. Here, when the substrate 22 vibrates, the energy of the sound radiated to the second space 25 is distributed to the vibration panel 23 and the substrate 22. Therefore, in this case, the sound pressure level reproduced from the vibration panel 23 is lower than when the substrate 22 does not vibrate. That is, the energy of the vibration of the vibration panel 23 is taken away by the vibration of the substrate 22, so that the vibration of the vibration panel 23 is reduced. As described above, it is necessary to prevent the substrate 22 from vibrating due to the sound pressure in the second space 25.

  As a method for preventing the vibration of the substrate 22, it is conceivable to increase the thickness of the substrate 22 so that the substrate 22 has sufficient strength. However, increasing the thickness of the substrate 22 will increase the thickness of the sound reproducing device. In particular, it is not preferable to increase the thickness of the substrate 22 in a portable terminal device aimed at miniaturization and weight reduction. Further, as another method for preventing the vibration of the substrate 22, it is conceivable to adhere the substrate 22 to the display screen of the display device 21 with an adhesive. However, if the substrate 22 and the display screen are bonded, the light transmittance is reduced by the bonding layer, and the image quality of the display screen is degraded. Therefore, it is necessary to provide the first space 28 between the substrate 22 and the display screen as shown in FIG.

  Therefore, in the first embodiment, the vibration of the substrate 22 is suppressed by sealing the first space 28. The vibration of the substrate 22 is suppressed by the acoustic stiffness of the air in the first space 28. By making the first space 28 a substantially closed space, vibration of the substrate 22 can be suppressed even if the substrate 22 has a thickness equal to or less than the vibration panel 23. Thus, it is possible to prevent the sound pressure of the vibration panel 23 from lowering due to the vibration of the substrate 22.

  Since the substrate 22 and the vibration panel 23 are made of a transparent material, the display screen of the display device 21 can be viewed from outside the sound reproducing device. Further, since the electroacoustic transducer 26 is disposed on the side surface of the display device 21, the electroacoustic transducer 26 does not block the display screen.

  As described above, according to the sound reproducing device of the first embodiment, it is possible to give the user a feeling that sound is being reproduced from the display device without deteriorating the sound quality of the reproduced sound. Further, by making the first space substantially closed, it is possible to prevent a decrease in the reproduced sound pressure. Furthermore, the substrate can be made thinner by forming the first and second spaces, so that the sound reproducing device can be made thinner.

  Note that the sound reproducing device according to Embodiment 1 can be manufactured with three components, that is, the substrate 22, the vibration panel 23, and the spacer 24 as separate bodies. That is, these three components are assembled, and a main body other than these components is manufactured. Then, by attaching a component obtained by assembling these three components to the main body, the sound reproducing device can be easily manufactured. Further, in the sound reproducing device according to the first embodiment, since the display screen of the display device is covered by the substrate 22 and the vibration panel 23, the display screen can be more reliably protected as compared with the configuration without the substrate 22. it can.

  In the first embodiment, the external shape of the electroacoustic transducer 26 is round, but may be elliptical or rectangular. The display screen of the display device 21 can be made larger by making the outer shape of the electric acoustic converter 26 elliptical or rectangular.

(Embodiment 2)
Next, an audio reproducing apparatus according to Embodiment 2 will be described with reference to FIGS. In the second embodiment, a sound reproducing device realized as a mobile phone will be described. FIG. 3 is a plan view showing the mobile phone according to the second embodiment with a cutout provided partially. FIG. 4 is a block diagram of the mobile phone according to the second embodiment.

  3 and 4, the mobile phone 100 includes an outer case 101, an antenna 102, a display device 103, a substrate 104, a vibration panel 105, a spacer 106, an electroacoustic transducer 110, a signal processing unit 111, and a signal amplification unit 112. Have. 3, an outer case 101 contains an electric circuit and the like included in the mobile phone 100. The antenna 102 is attached to the outer case 101. In FIG. 3, a cutout is provided in a part of the vibration panel 105. In FIG. 4, the signal processing unit 111 is connected to the antenna 102 and the signal amplification unit 112. Further, the signal amplifying unit 112 is connected to the signal processing unit 111 and the electroacoustic transducer 110. The configuration of the sound reproducing device 113 indicated by a dotted line in FIG. 4 is the same as that of the first embodiment except for the outer shape of the outer case 101.

  Next, the operation of the mobile phone 100 according to Embodiment 2 will be described. The signal received by the antenna 102 is input to the signal processing unit 111. Here, it is assumed that a reception signal indicating a reception sound, which is the voice of the sender, is received by antenna 102. The signal processing unit 111 performs predetermined signal processing on a signal input from the antenna 102. For example, a process of extracting a reception signal from the input signal is performed. The signal subjected to the signal processing is amplified by the signal amplifier 112 and applied to the electroacoustic transducer 110. The point that sound is emitted from vibration panel 105 when an electric signal is applied to electroacoustic transducer 110 is the same as in the first embodiment. As described above, the vibration panel 105 operates as a receiver that is a speaker for reproducing the received sound. Since the vibration panel 105 vibrates almost uniformly due to the sound pressure in the second space 109, a receiver having a wide listening range capable of listening to the received sound regardless of the position of the ear on the vibration panel 105 is provided. realizable.

  Next, the effect of the first space 108 in the second embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating a measuring device that measures receiver characteristics of the sound reproducing device according to the second embodiment. In FIG. 5, the measurement device includes a measurement cover 120, an acoustic coupler 122, and a measurement microphone 123. The measurement cover 120 is attached to the vibration panel 105 so as to form a closed space 121 between the measurement cover 120 and the vibration panel 105. The acoustic coupler 122 has ear acoustic characteristics in accordance with the international standard IEC (International Electrotechnical Commission). In the measuring device shown in FIG. 5, the sound radiated from the vibration panel 105 is guided to the acoustic coupler 122 through the closed space 121, and the sound pressure frequency characteristic is measured by the measuring microphone 123.

  FIG. 6 is a diagram showing a result of measuring a sound pressure frequency characteristic of the sound reproducing device by the measuring device shown in FIG. In FIG. 6, the vertical axis represents the sound pressure of the sound radiated from the sound reproducing device, and the horizontal axis represents the frequency of the sound. Here, the electroacoustic transducer 110 is an electrodynamic speaker having a diameter of 10 mm, the substrate 104 is a transparent acrylic material having a material thickness of 0.65 mm, the vibration panel 105 is 60 mm long by 40 mm wide, and has a thickness of 0.3 mm. 190 mm transparent PET material. The gap width of the first space 108 is 0.5 mm, the gap width of the second space 109 is 0.2 mm, and the gap width of the sealed space 121 on the front surface of the vibration panel 105 is 0.2 mm.

  I shown in FIG. 6 shows a sound pressure frequency characteristic when the first space 108 exists on the back surface of the substrate 104. Further, II shown in FIG. 6 shows a sound pressure frequency characteristic when the first space 108 does not exist on the back surface of the substrate 104. When the first space 108 does not exist, the substrate 104 vibrates due to the sound pressure radiated from the electroacoustic transducer 110 to the second space 109. As a result, acoustic energy for vibrating the vibration panel 105 is consumed, so that the sound pressure radiated from the vibration panel 105 is reduced. On the other hand, when the first space 108 exists, the acoustic stiffness due to air in the first space 108 is large, and the vibration of the substrate 104 is suppressed. In other words, in this case, although the substrate 104 has a thin material thickness of 0.65 mm, it acts as if it were a rigid body. As a result, the sound pressure level is higher by about 3 to 10 dB in the frequency band of 1 kHz or less than in the case where the first space 108 does not exist. Thus, it can be seen that the provision of the first space 108 can significantly reduce the loss of acoustic energy due to the substrate 104.

  As described above, the same effect as in the first embodiment can be obtained by the mobile phone 100 according to the second embodiment. In the second embodiment, the signal applied to electroacoustic transducer 110 has been described as a reception signal. Here, an incoming signal, a music signal, a voice signal, or a signal indicating a sound effect of a game that indicates an incoming call may be received by the antenna 102, and these signals may be applied to the electroacoustic transducer 110. At this time, the vibration panel 105 functions as a loudspeaker for reproducing a ringtone, music, voice, or a game sound effect. When mobile phone 100 according to Embodiment 2 has a videophone function, the face of a conversation partner is displayed on a display screen, and a voice is reproduced on vibration panel 105. In a conventional sound reproducing apparatus in which a driver is directly attached to an outer case, it is necessary to use most of the outer case as a vibration surface in order to reproduce sound with a sufficient sound pressure. Therefore, the space for mounting the display device is limited, and a large display screen cannot be used (see FIG. 12). On the other hand, in the second embodiment, since the vibration panel 105 is acoustically driven, a mobile phone equipped with a large display screen, which cannot be realized by a conventional mobile phone, can be realized.

(Embodiment 3)
Next, an audio reproducing apparatus according to Embodiment 3 will be described with reference to the drawings. The sound reproduction device according to the third embodiment is realized as a portable terminal device, as in the first embodiment. The sound reproducing device according to Embodiment 3 has a configuration including two electroacoustic transducers.

  FIG. 7 is a diagram showing a sound reproducing device according to Embodiment 3. 7A is a plan view of the sound reproducing device, and FIG. 7B is a cross-sectional view of the sound reproducing device taken along a line CD. 7, the sound reproducing device includes an outer case 130, a display device 131, a substrate 132, a vibration panel 134, a spacer 140, a first electro-acoustic transducer 136, and a second electro-acoustic transducer 138. In the third embodiment, first sound hole 137 and second sound hole 139 are provided in substrate 132 and outer case 130. The first and second electroacoustic transducers 136 and 138 are disposed on the opposite side of the substrate 132 from the second space 135. The first electroacoustic transducer 136 is connected to the outer case 130 so as to cover the first sound hole 137. The second electroacoustic transducer 138 is connected to the outer case 130 so as to cover the second sound hole 139. The configuration is the same as that of the first embodiment except for the configuration of the first and second electroacoustic transducers 136 and 138 and the first and second sound holes 137 and 139. The operating principle in which the vibration panel 134 vibrates when an electric signal is applied to at least one of the first and second electroacoustic transducers 136 and 138 is the same as in the first embodiment.

  Further, the mobile terminal device according to Embodiment 3 can be used as a mobile phone as described in Embodiment 2. FIG. 8 is a block diagram in the case where the mobile terminal device according to Embodiment 3 is used as a mobile phone. In FIG. 8, the mobile phone includes a sound reproducing device 150, an antenna 151, a signal processing unit 152, a first signal amplifying unit 153, and a second signal amplifying unit 154. The sound reproducing device 150 is the sound reproducing device shown in FIG. The signal processing unit 152 is connected to the antenna 151 and the first and second signal amplification units 153 and 154. The first signal amplification section 153 is connected to the first electroacoustic transducer 136. The second signal amplifier 154 is connected to the second electroacoustic transducer 138.

  Next, the operation of the mobile phone shown in FIG. 8 will be described. The antenna 151 receives a signal transmitted from a base station of a mobile phone. This signal includes an incoming signal, a reception signal indicating a reception sound, an audio signal such as music, or an image signal such as a moving image or character information. The signal received by the antenna 151 is subjected to signal processing in the signal processing unit 152, and is input to one of the first and second signal amplification units 153 and 154. Here, when the reception signal is included in the signal received by the antenna 151, the signal processing unit 152 outputs the reception signal subjected to the signal processing to the first signal amplification unit 153. As a result, the received signal is amplified by the first signal amplifier 153 and applied to the first electroacoustic transducer 136. At this time, the vibration panel 134 operates as a receiver. On the other hand, when the signal received by the antenna 151 includes a signal other than the reception signal, the signal processing unit 152 outputs the processed signal to the second signal amplification unit 154. Here, the signal other than the reception signal is, for example, the sound signal, an incoming call signal indicating that there is an incoming call, a music signal downloaded from the Internet, or the like. These signals are amplified by the second signal amplifier 154 and applied to the second electroacoustic transducer 138. At this time, the vibration panel 134 operates as a loudspeaker.

  In general, for an electroacoustic transducer operated as a receiver, the lowest resonance frequency of the vibration system is set to around 250 Hz to 550 Hz in consideration of sound leakage from the ear. Since it is assumed that the receiver listens while approaching the ear, the input signal to the electroacoustic transducer operated as the receiver is as small as 40 mW or less. Therefore, even if the lowest resonance frequency of the electro-acoustic transducer is low, abnormal noise and destruction do not occur due to the large amplitude of the vibration system. On the other hand, a signal having a large value of 200 mW or more is applied to a loudspeaker for loudspeaker which reproduces a sound louder than a receiver. Therefore, it is difficult to lower the lowest resonance frequency of the electroacoustic transducer operating as a loudspeaker too much, and the electroacoustic transducer operating as a loudspeaker can reproduce a large sound pressure level. Requires a simple structure and shape. As described above, it is difficult to use a single electro-acoustic transducer for sound reproduction having different uses as a receiver and a speaker for loudspeakers. Here, Embodiment 3 employs a configuration including an electro-acoustic transducer that operates as a receiver and an electro-acoustic transducer that operates as a speaker for loudspeakers. Therefore, the configuration of the third embodiment is a more practical configuration than the configuration of the second embodiment in which one electroacoustic transducer performs both operations of a receiver and a speaker for loudspeakers.

  Note that the user normally listens to the sound received by the receiver with his / her ear close to the vibration panel. On the other hand, the melody sound and the like reproduced by the loudspeaker are reproduced with a loud sound compared to the reception sound. Therefore, when the user brings the portable terminal device close to the ear to listen to the reception sound, a loud melody sound is reproduced, and the reproduced melody sound may impair the user's hearing. Here, in the third embodiment, since two electroacoustic transducers are arranged at positions separated according to the application, there is little direct influence from the electroacoustic transducer, and one electroacoustic transducer is used. Security is higher than in the second embodiment used.

(Embodiment 4)
Next, an audio reproducing apparatus according to Embodiment 4 will be described with reference to FIG. The sound reproduction device according to the fourth embodiment is realized as a portable terminal device, as in the first embodiment. In the sound reproducing device according to Embodiment 4, the vibration panel and the substrate are configured by a touch panel.

  FIG. 9 is a diagram showing a sound reproducing device according to Embodiment 4. FIG. 9A is a plan view in which a part of the sound reproducing device is cut away, and FIG. 9B is a cross-sectional view taken along a line EF of the sound reproducing device.

  In FIG. 9, the sound reproducing device includes an outer case 159, a display device 160, a substrate 161, a first transparent electrode 162, a vibrating panel 164, a second transparent electrode 165, a spacer 166, resistance value detecting electrodes 168 to 171, And an electroacoustic transducer 173.

  The sound reproducing device according to the fourth embodiment is different from the sound reproducing device according to the first embodiment in that the sound reproducing device further includes first and second transparent electrodes 162 and 165 and resistance value detecting electrodes 168 to 171. It is. The first transparent electrode 162 is connected to the substrate 161 so as to face the second space 167. The second transparent electrode 165 is connected to the vibration panel 164 so as to face the second space 167. The resistance value detecting electrodes 168 and 169 are provided on the short side of the spacer 166. Further, the resistance value detection electrodes 168 and 169 are provided between the spacer 166 and the second transparent electrode 165. Therefore, the resistance value detecting electrodes 168 and 169 are in contact with the second transparent electrode 165. On the other hand, the resistance value detecting electrodes 170 and 171 are provided on the long side of the spacer 166. The resistance value detecting electrodes 170 and 171 are provided between the spacer 166 and the first transparent electrode 162. Therefore, the resistance value detecting electrodes 170 and 171 are in contact with the first transparent electrode 162.

  The sound reproducing device according to the first embodiment is different from the sound reproducing device according to the first embodiment in that the substrate 161, the first transparent electrode 162, and the sound hole 172 provided in the outer case 159 are rectangular. Is different from Except for the points described above, the configuration of the sound reproduction device according to Embodiment 4 is the same as the configuration of the sound reproduction device according to Embodiment 1.

  The operation of reproducing sound by vibrating the vibration panel 164 of the sound reproducing device is the same as in the first embodiment. Here, in the sound reproducing device according to the fourth embodiment, the first and second transparent electrodes 162 and 165 and the resistance value detecting electrodes 168 to 171 form a touch panel. That is, when the vibration panel 164 is pressed by a pen or a user's finger, the first transparent electrode 162 and the second transparent electrode 165 come into contact with each other. The coordinates indicating the contact position are detected by the resistance detection electrodes 168 and 169 and the resistance detection electrodes 170 and 171 as a change in resistance. The operation of the sound reproducing device is controlled based on the detected coordinates. Although not shown in FIG. 9, an operation menu, icons, and the like are displayed on the display screen of the display device 160.

  As described above, in the fourth embodiment, the touch panel serving as the input device and the vibration panel for reproducing the sound can be shared, and the sound reproduced from the touch panel without interrupting the image on the display screen can be used. A playback device can be realized. Note that the touch panel detection method is not limited to a method using a change in electric resistance, and may be a method using light, capacitance, or the like.

  The sound reproducing device shown in FIG. 9 includes a circuit for processing a signal detected by the touch panel, a circuit for controlling the sound reproducing device based on the signal, and the like. , And detailed description and explanation are omitted.

  As described above, according to the present invention, it is possible to give the user a feeling that sound is being reproduced from the display device without deteriorating the sound quality of the reproduced sound. Further, by making the first space substantially closed, it is possible to prevent a decrease in the sound pressure for reproduction and to make the sound reproduction device thin.

  In addition, if the sound reproducing apparatus according to the present invention is applied to a mobile phone and a vibration panel is arranged on a display screen of the mobile phone, the vibration panel can be operated as a receiver for receiving sound. It becomes. At this time, since the received sound is reproduced from the front of the vibration panel, it is possible to listen over a wide range of the vibration panel surface, and it is possible to realize a mobile phone in which the elderly person can easily hear the received sound. Also, by increasing the level of the input signal applied to the sound reproducing device, the vibrating panel can be operated as a loudspeaker. As a result, it is possible to have a conversation while watching the image like a videophone. Also, since the radiation surface of the image and the sound is the same surface, it is possible to give the user a feeling that sound is coming out of the image, and to realize an optimal sound reproduction device for simultaneous reproduction of sound and video. Can be.

  Further, by using the surface film of the touch panel also as the vibration panel, a portable terminal device in which the input device and the sound reproducing device are integrated can be realized.

  In the first to fourth embodiments, the structure of the electro-dynamic loudspeaker has been described as an example of the electro-acoustic transducer 26, but the electro-acoustic transducer 26 may be of any type. The electro-acoustic transducer 26 may have any function of emitting sound from the diaphragm, and may be of any type such as an electromagnetic type, a piezoelectric type, and an electrostatic type.

  In the present invention, “sealing the first space” does not necessarily mean that the first space is a completely closed space. The first space 28 may be a substantially closed space. Hereinafter, this will be described with reference to FIG.

  FIG. 10 is a diagram showing a sound pressure frequency characteristic of the sound reproducing device according to the present invention. FIG. 10 shows the results of measuring the sound radiated from the vibration panel of the sound reproduction device according to Embodiment 2 using the sound coupler shown in FIG. In FIG. 10, the size of the substrate and the size of the vibration panel are each 40 × 60 mm, and the thicknesses thereof are each 0.2 mm. The solid line shown in FIG. 10 shows the sound pressure frequency characteristics when no pore is provided in the first space. The dotted line shown in FIG. 10 is a sound pressure frequency characteristic when a pore having a diameter of 1 mm is provided in the first space. The one-dot chain line shown in FIG. 10 is a sound pressure frequency characteristic when a pore having a diameter of 2 mm is provided in the first space.

  As is clear from FIG. 10, when the pores are provided in the first space, the sound pressure is lower in a band of 400 Hz or less than in the case where no pores are provided. This is because the acoustic stiffness of the first space is reduced by the pores, and the force for suppressing the vibration of the substrate 104 is reduced. Here, when the diameter of the pore is 1 mm, the sound pressure level decreases in a low sound range of 300 Hz or less, but does not decrease in a band of 300 Hz or more. Considering the case where the sound reproducing device is realized as a mobile phone, the band necessary for reproducing the received sound is a frequency band higher than 300 Hz. Therefore, in the example of FIG. 10, when operating as a receiver of a mobile phone, there is no problem even if the first space has a pore having a diameter of about 1 mm. As described above, it is desirable that the first space is completely sealed. However, a sufficient effect can be obtained even if the first space is opened to some extent. In FIG. 5, the acoustic coupler acts as an acoustic load and suppresses the vibration of the vibration panel 105. Therefore, in FIG. 5, it is considered that the substrate 104 is more likely to vibrate than when no acoustic coupler is provided. That is, there is no acoustic coupler when the mobile phone is normally used, so the effect of the pores is considered to be actually smaller than in the case of FIG. In view of the above, it is considered that there is no problem in some cases even if the size of the pores is 1 mm or more in diameter.

  Further, in the first to fourth embodiments, the case where the sound reproducing device is realized as a portable terminal device which is a portable electronic device has been described. However, the sound reproducing device according to the present invention may be implemented by a game machine or a personal computer. Alternatively, the present invention can be applied to a stationary electronic device such as a television.

  Further, in Embodiments 1, 2, and 4, the number of electroacoustic transducers and sound holes is one. However, as described in Embodiment 3, the number of electroacoustic transducers and sound holes is plural. You may. When there are a plurality of electroacoustic transducers and a plurality of sound holes, the same signal can be applied to all electroacoustic transducers to reproduce sound at a large volume. Further, a stereo signal may be applied to two electroacoustic transducers.

  Further, in another embodiment, a poster or a photograph on which an image is drawn may be used instead of the display device. For example, if a sound reproducing device is applied to a photo stand, it is possible to give the user a feeling that sound is being reproduced from a photograph.

  The sound reproducing device of the present invention can be used not only as a mobile terminal device such as a mobile phone or a PDA, but also as a stationary personal computer or a television.

FIG. 1 is a diagram showing a configuration of a sound reproducing device according to Embodiment 1. Sectional view of the electroacoustic transducer shown in FIG. FIG. 9 is a plan view showing the mobile phone according to the second embodiment with a cutout provided partially. Block diagram of mobile phone according to Embodiment 2. The figure which shows the measuring device which measures the receiver characteristic of the sound reproduction apparatus which concerns on Embodiment 2. The figure which shows the result of having measured the sound pressure frequency characteristic of the sound reproduction apparatus with the measuring apparatus shown in FIG. The figure which shows the sound reproducing apparatus which concerns on Embodiment 3. Block diagram when mobile terminal device according to Embodiment 3 is used as a mobile phone FIG. 9 is a diagram showing an audio reproducing apparatus according to Embodiment 4. FIG. 4 is a diagram showing a sound pressure frequency characteristic of the sound reproducing device according to the present invention. External perspective view of a television set provided with a conventional sound reproducing device External view of a mobile phone equipped with a conventional sound reproducing device

Explanation of reference numerals

20, 101, 130, 159 Outer case 21, 103, 131, 160 Display device 22, 104, 132, 161 Substrate 23, 105, 134, 164 Vibration panel 24, 106, 140, 166 Spacer 26, 110, 136, 138 , 173 Electroacoustic transducer

Claims (6)

Display means for displaying an image on a display surface;
A first space is formed between the display means and the display surface, and a substrate made of a material that transmits visible light;
A vibration panel that is disposed on the opposite side of the display means with respect to the substrate, forms a second space between the substrate and the substrate, and is made of a material that transmits visible light;
A sound reproducing device comprising: at least one electroacoustic transducer that emits sound to the second space. The substrate is provided with a sound hole,
The sound reproducing device according to claim 1, wherein the electroacoustic transducer emits sound to the second space via the sound hole. Further comprising a case having an opening covered by the vibration panel,
The sound reproducing device according to claim 1, wherein the case includes the substrate, the display unit, and the electroacoustic transducer therein.   The sound reproducing device according to claim 3, wherein the vibration panel is configured by a touch panel. An antenna for receiving the signal,
4. The sound reproducing apparatus according to claim 3, further comprising: a signal processing unit configured to perform predetermined signal processing on a signal received by the antenna and input the processed signal to the electroacoustic transducer. The sound reproducing device includes two of the electroacoustic transducers,
When the signal received by the antenna includes a signal indicating a reception sound, the signal processing unit inputs the signal to one of the electroacoustic transducers, and outputs the reception sound to the signal received by the antenna. The sound reproducing device according to claim 5, wherein when a signal other than the signal indicating is included, the signal is input to the other electroacoustic transducer.

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