JP2008278328A - Speaker system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker system in which speakers stably operate and can be made compact, lightweight, and low-cost. <P>SOLUTION: A rechargeable battery 11 is used as the power source of a cordless speaker system 2, an AC adapter 15 having a charging unit 16 can be connected to a system main body 2a, and the charging unit 16 fully charges the rechargeable battery 11 for next use. Further, a lithium ion secondary battery which can be charged fast with a current of ≥10C is used as the built-in rechargeable battery 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cordless speaker system used for a portable music player or the like.

  Recently, as portable audio devices, there are many portable music players that are equipped with a flash memory or HDD, can store a large number of music pieces, and can reproduce them. Some mobile phones also incorporate a music player function, and possessing such a mobile phone makes it possible to listen to music as well as to make calls.

  By the way, portable electronic devices such as music players and mobile phones can be enjoyed outdoors by carrying them, and usually listen to music using headphones. .

  However, those who have such portable electronic devices not only listen to music outdoors, but also want to listen to music even in rooms such as their homes. When listening, it may seem annoying to use headphones and may not enjoy music.

  Therefore, recently, a method of listening to music from a speaker without using headphones by conceiving a speaker separately and connecting the speaker to a music player with a cable or the like has been considered. In this case, if the speaker is small, it can be used as a movable music player system by freely moving indoors.

  However, when a speaker is connected to the music player via a cable, for example, when moving to another room, the music player and the speaker are moved while the cable is connected, and an AC power source is used as a power source for the speaker. If used, the AC adapter and power cord must be moved together, which makes handling extremely troublesome.

  Also, if you connect a speaker to a music player via a cable and make it into a system, if you want to take out only the music player suddenly to go out, it will be cumbersome to disconnect the cable and change it to headphones It takes time and effort. In addition, there are restrictions on the place to use, for example, bringing a music player that does not have a waterproof function into a wet place such as a kitchen or bathroom may cause trouble.

Therefore, recently, as disclosed in Patent Document 1, there is a speaker system that is made cordless by wirelessly transmitting an audio signal from an audio device. In this case, the speaker system uses a rechargeable secondary battery as an internal power source.
JP 2004-328692 A JP-A-2005-123183

  If the speaker system is made cordless in this way, the audio device and the speaker system can be used separately from each other, so that the handling can be made extremely convenient compared to the case using a cable. In addition, by using a rechargeable secondary battery as an internal power supply, it is not necessary to replace a battery such as a dry battery, so there is an advantage that the cost can be reduced.

  However, when a secondary battery is used as a power source, the remaining battery level becomes a problem. If the speaker system is continuously used when the remaining battery level is low, the playback sound from the speaker can be maintained stably. It becomes difficult. For this reason, it is necessary to charge the secondary battery frequently by connecting to the AC power supply via the power cord so that the remaining battery level of the secondary battery can always maintain a predetermined value or more, and the speaker system is made cordless. The benefits will fade. Further, if such frequent recharging of the secondary battery is neglected, when the speaker system is used frequently and continuously used, the battery may run out. When the battery runs out, for example, a nickel hydride storage battery that is generally used, it takes about 12 hours for normal charging and 2 to 3 hours for quick charging. During this time, the speaker system cannot be used. .

  Therefore, it is conceivable to install a secondary battery having a large capacity so that the speaker system can be used continuously for a long time. However, since such a large-capacity secondary battery is itself large, if such a secondary battery is incorporated in the speaker system, the entire speaker system becomes large and heavy, and it is easy to use. It will be extremely bad.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a speaker system in which stable operation of a speaker is possible, and which can be reduced in size and weight and reduced in cost.

  According to the first aspect of the present invention, an audio signal wirelessly transmitted from the outside is received by wireless communication means, and a system main body for driving the speaker by amplifying the received audio signal is provided inside the system main body. And a rechargeable battery that can be rapidly charged with a current of 10 C or more, which is used as a power source for supplying power necessary for the operation of the system main body.

  The invention according to claim 2 further comprises a charging means in the invention according to claim 1, and the charging means is electrically connectable to the system main body and charges the rechargeable battery in the connected state. It has a charging part.

  A third aspect of the invention is characterized in that, in the first aspect of the invention, the system main body has a remaining battery capacity display means for displaying a remaining battery capacity of the rechargeable battery.

  The invention according to claim 4 is the monitoring according to claim 1, further comprising detecting at least one of overcharge, overdischarge and overcurrent of the rechargeable battery and stopping charging or discharging of the rechargeable battery. It has a protective means.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the audio signal received by the wireless communication means is from a portable music player or mobile phone having the wireless communication means. It is characterized by being.

  ADVANTAGE OF THE INVENTION According to this invention, the speaker system which can operate | move the speaker stably, and can aim at size reduction, weight reduction, and cost reduction can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIGS. 1A and 1B show a schematic configuration of a speaker system used in the portable music player according to the first embodiment of the present invention.

  In FIG. 1A, reference numeral 1 denotes a music player as a portable electronic device. This music player 1 is equipped with a flash memory and an HDD, stores a large number of music pieces, and can select and reproduce them. Is. In this case, many known music players 1 of various types have been put into practical use, and detailed description thereof will be omitted here.

  The music player 1 includes a wireless communication unit 1a (see FIG. 2) that performs short-distance wireless communication such as Bluetooth (registered trademark) as a wireless communication unit, and an audio signal reproduced by the music player 1 is received. Modulation is performed by the wireless communication unit 1a to enable transmission to the outside. Here, Bluetooth is an interface standard for short-range wireless communication of about 10 m, and the maximum communication speed is 1 Mbit / sec and uses a frequency of 2.4 GHz band.

  The speaker system 2 of the present embodiment shown in FIG. 1B is applied to such a music player 1. In this case, the speaker system 2 has a system main body 2a, and two speakers 2b and 2c are arranged on both sides of the system main body 2a. In the illustrated example, the example of the two speakers 2b and 2c has been described. However, one speaker may be used.

  In the system main body 2a, the operation unit 3 is disposed in the front center portion. The operation unit 3 is provided with a display unit for displaying the reproduction volume of the speakers 2b and 2c, a volume for adjusting the volume, and the like (both not shown). A power switch 4 and an AC adapter connection terminal 5 are disposed below the operation unit 3, and a battery remaining amount display unit 6 is disposed above the operation unit 3. The power switch 4 turns on / off the power of the system main body 2a. The AC adapter connection terminal 5 includes a cylindrical positive electrode 5a disposed in the hole and a rod-shaped negative electrode 5b disposed on the central axis of the positive electrode 5a. Fifteen plugs 19 are electrically connected. In this case, the AC adapter connection terminal 5 is provided with a lid (not shown), and when the AC adapter connection terminal 5 is not used, the hole of the AC adapter connection terminal 5 is closed with the lid. With a waterproof function. In this case, the speaker system 2 has a waterproof function throughout the system.

  The battery remaining amount display unit 6 displays a discharge state of the rechargeable battery 11 to be described later. The light emitter is turned on when the battery remaining amount is equal to or higher than a predetermined value, and blinks when the battery remaining amount is lower than the predetermined value. For example, an LED is used as the light emitter. In this case, for example, a blue LED may be turned on when the remaining charge amount is equal to or greater than a predetermined value, and a red LED may be turned on when the remaining battery amount falls below a predetermined value.

  FIG. 2 shows a circuit configuration of the system main body 2 a of the speaker system 2. In FIG. 2, the same parts as those in FIG.

  In FIG. 2, 11 is a rechargeable battery. This rechargeable battery 11 is provided in the system main body 2a, and is used as a power supply required for operation | movement of the system main body 2a. As the rechargeable battery 11, a lithium ion secondary battery capable of rapid charging is used in the present embodiment. The lithium ion secondary battery includes a container made of an exterior member made of an aluminum laminate film, a non-aqueous electrolyte housed in the container, and a positive electrode current collector made of aluminum foil and housed in the container. A positive electrode carrying a positive electrode layer containing as a positive electrode active material, and a negative electrode carrying a negative electrode layer containing lithium titanium oxide as negative electrode active material particles in a negative electrode current collector made of aluminum foil and housed in the container. It has the structure provided.

  Here, the lithium ion secondary battery will be described in more detail. Such a lithium ion secondary battery includes a negative electrode containing lithium titanium oxide as an active material. As disclosed in Patent Document 2, lithium titanium oxide as an active material is a material capable of inserting and extracting lithium, and insertion / extraction of lithium ions is performed in the vicinity of 1.4 V to 1.7 V / Li. . For this reason, even if the secondary battery is rapidly charged with a large current, it is possible to ensure safety without causing lithium deposition compared to the case where a carbon material is used as a conventional negative electrode active material. In addition, since expansion and contraction associated with insertion and extraction of lithium can be suppressed, structural destruction of the negative electrode active material can be suppressed even when rapid charging with 20 C current is repeatedly performed. As a result, a long life can be maintained even when charging and discharging are repeated. Since the potential of the battery is about 2.4 V, it corresponds to two conventional nickel-metal hydride storage batteries or nickel cadmium storage batteries in series, so that a reduction in use of 50% can be achieved.

  Specifically, it was confirmed that the lithium ion secondary battery assembled by the following method is a fast charge secondary battery that can be charged to about 80% battery capacity by charging at 20 C for 3 minutes. ing. Here, “C” is a unit representing a charge / discharge rate, and a rate that can be calculated in one hour when a constant current charge from full discharge to full charge (or from full charge to full discharge) is calculated is expressed as 1C. In the case of 1/10 hour, it is expressed as 10C. Therefore, for example, 20C charging requires 20 times as much current as 1C charging.

<Production of negative electrode>
As an active material, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) powder having an average particle diameter of 5 μm and an Li storage potential of 1.55 V (vs. Li / Li ⁺ ), and carbon having an average particle diameter of 0.4 μm as a conductive agent. The powder and polyvinylidene fluoride (PVdF) as a binder were blended in a weight ratio of 90: 7: 3, and these were dispersed in an n-methylpyrrolidone (NMP) solvent to prepare a slurry.

  In addition, the laser diffraction type particle size distribution measuring apparatus (Shimadzu Corporation model number SALD-300) was used for the measurement of the particle diameter of an active material. First, about 0.1 g of a sample was put in a beaker or the like, and then a surfactant and 1 to 2 mL of distilled water were added and stirred sufficiently, and poured into a stirred water tank. The light intensity distribution was measured 64 times at intervals of 2 seconds, the particle size distribution data was analyzed, and the particle size (D50) having a cumulative frequency distribution of 50% was defined as the average particle size.

Next, an aluminum foil (purity: 99.99%) having a thickness of 10 μm was applied to the negative electrode current collector, dried, and then pressed to prepare a negative electrode having an electrode density of 2.4 g / cm ³ .

<Preparation of positive electrode>
Lithium cobalt oxide (LiCoO ₂ ) as an active material, graphite powder as a conductive material, and polyvinylidene fluoride (PVdF) as a binder are blended in a weight ratio of 87: 8: 5. -A slurry was prepared by dispersing in a methylpyrrolidone (NMP) solvent. The slurry was applied to an aluminum foil (purity 99.99%) having a thickness of 15 μm, dried, and pressed to prepare a positive electrode having an electrode density of 3.5 g / cm ³ .

<Assembly of secondary battery>
An aluminum-containing laminate film having a thickness of 0.1 mm was prepared as a forming material for the container (exterior member). The aluminum layer of this aluminum-containing laminate film had a thickness of about 0.03 mm. Polypropylene was used as the resin for reinforcing the aluminum layer. By laminating this laminate film by thermal fusion, a container (exterior member) was obtained and further contained in a metal aluminum container.

  Next, a positive electrode terminal was electrically connected to the positive electrode, and a negative electrode terminal was electrically connected to the negative electrode. A separator made of a polyethylene porous film having a thickness of 12 μm was coated in close contact with the positive electrode. The positive electrode covered with the separator was overlapped with the negative electrode so as to face each other, and these were wound in a spiral shape to produce an electrode group. This electrode group was pressed into a flat shape. An electrode group formed into a flat shape was inserted into a container (exterior member).

LiBF ₄ , which is a lithium salt, is dissolved in an organic solvent in which ethylene carbonate (EC) and γ-butyllactone (GBL) are mixed at a volume ratio (EC: GBL) of 1: 2 to obtain a liquid. A non-aqueous electrolyte was prepared. The obtained nonaqueous electrolyte was poured into the container to assemble a lithium secondary battery. Such a lithium secondary battery can be used at a full charge voltage of 2.8 V and a discharge end voltage of 1.5 V.

  In this embodiment, as the rechargeable battery 11, a battery that can be charged to about 80% battery capacity by charging at 20C for 3 minutes and that can be charged 90% or more by further charging for 5 minutes is used.

  The rechargeable battery 11 is connected to a control unit 12 as a control unit. The control unit 12 is connected to the operation unit 3 and the battery remaining amount display unit 6 described above, and is further connected to a wireless communication unit 13 as wireless communication means. The wireless communication unit 13 performs Bluetooth wireless communication with the wireless communication unit 1a on the music player 1 side, receives the audio signal transmitted from the wireless communication unit 1a, and demodulates the original audio signal.

  In addition, the control unit 12 includes a speaker driving unit 121 and a battery remaining amount monitoring unit 122. The speaker driving unit 121 amplifies the power of the audio signal demodulated by the wireless communication unit 13 and drives the speakers 2b and 2c. The battery remaining amount monitoring means 122 monitors the discharge state of the rechargeable battery 11, turns on the light emitter of the battery remaining amount display unit 6 when the battery remaining amount is a predetermined value or more, and emits light when the battery remaining amount falls below the predetermined value. Make your body blink.

The rechargeable battery 11 is provided with a monitoring protection circuit 14 as monitoring protection means. The monitoring protection circuit 14 monitors the state of the rechargeable battery 11, and stops charging / discharging of the rechargeable battery 11 by driving a switch (not shown) according to the monitoring result. In this case, the monitoring protection circuit 14 monitors overcharge, overdischarge, and overcurrent of the rechargeable battery 11. When the charging voltage of the rechargeable battery 11 is within a predetermined value range, charging / discharging of the rechargeable battery 11 is allowed. ) Is released to stop the charging of the rechargeable battery 11, and when the charging voltage of the rechargeable battery 11 falls below a predetermined value, it is determined that the battery is overdischarged and the switch (not shown) is opened to open the rechargeable battery 11. Stop the discharge. Further, when the discharge current of the rechargeable battery 11 exceeds a predetermined value, it is determined as an overcurrent, and the switch (not shown) is opened to stop the discharge of the rechargeable battery 11. This prevents the rechargeable battery 11 from being overcharged and generating gas due to the decomposition of the electrolyte, increasing the pressure inside the battery and preventing leakage, and the rechargeable battery 11 to be in an overdischarged state. Thus, the copper of the negative electrode current collector is prevented from being dissolved by the electrolytic solution and deteriorating the battery performance. Such a monitoring protection circuit 14 is modularized and used as a unit integrated into the rechargeable battery 11.
Note that the monitoring protection circuit 14 may monitor at least one of overcharge, overdischarge, and overcurrent of the rechargeable battery 11.

  The AC adapter connection terminal 5 is connected to the rechargeable battery 11. In this case, the positive terminal of the rechargeable battery 11 is connected to the positive electrode 5a of the AC adapter connection terminal 5, and the negative terminal of the rechargeable battery 11 is connected to the negative electrode 5b.

  An AC adapter 15 can be connected to the AC adapter connection terminal 5 of the system main body 2a. The AC adapter 15 includes a charging unit 16 and an AC / DC converter 17 as charging means. The charging unit 16 charges the rechargeable battery 11 with a direct current output from the AC / DC converter 17 until it is fully charged. The AC / DC converter 17 converts alternating current power into direct current power, and here generates a direct current voltage of about 3 V from a 100 V commercial power source supplied via the power cord 18.

  As shown in FIG. 3, a plug 19 corresponding to the AC adapter connection terminal 5 of the system main body 2a is connected to the AC adapter 15. The plug 19 includes a cylindrical positive electrode 19a and a cylindrical negative electrode 19b disposed on the central axis of the positive electrode 19a via an insulator. The positive electrode 19a and the plug 19 The negative electrode 19b is connected to the positive / negative output terminal of the charging unit 16. The positive side electrode 19a is inserted into the cylindrical positive side electrode 5a of the AC adapter connection terminal 5, and at the same time, the negative side electrode 5b having a rod shape is inserted into the positive side electrode 19a. 16 is electrically connected to the rechargeable battery 11 of the system main body 2a.

  Next, the operation of the embodiment configured as described above will be described.

  First, the plug 19 of the AC adapter 15 is inserted into the AC adapter connection terminal 5 of the system main body 2a, and the rechargeable battery 11 is charged to full charge by the charging unit 16. The user confirms that the rechargeable battery 11 is fully charged because the light emitter of the battery remaining amount display unit 6 is continuously lit. When the full charge of the rechargeable battery 11 is confirmed, the plug 19 of the AC adapter 15 is disconnected from the AC adapter connection terminal 5 of the system main body 2a.

  In this state, the cordless speaker system 2 is used for the portable music player 1. In this case, when the audio signal reproduced by the music player 1 is modulated and transmitted by the wireless communication unit 1a, in the speaker system 2, the wireless communication unit 13 of the system body 2a communicates with the wireless communication unit 1a via Bluetooth wireless communication. The audio signal is received by communication and demodulated into the original audio signal. The demodulated audio signal is amplified by the speaker driving means 121 to drive the speakers 2b and 2c.

  On the other hand, the remaining battery level monitoring unit 122 monitors the remaining battery level of the rechargeable battery 11. When the remaining battery level falls below a predetermined value, the light emitter of the remaining battery level display unit 6 blinks. When the user confirms the display of the battery remaining amount display unit 6, the plug 19 of the AC adapter 15 is inserted into the AC adapter connection terminal 5 of the system main body 2a, and the rechargeable battery 11 is charged to the full charge again for the next use. Prepare.

  Therefore, in this way, the rechargeable battery 11 is used as the power source of the cordless speaker system 2, and the AC adapter 15 having the charging unit 16 can be connected to the system main body 2a. 11 was fully charged, enabling the next use. Moreover, as the rechargeable battery 11 to be incorporated, a lithium ion secondary battery that can be rapidly charged with a current of 10 C or more is used.

  Thereby, the rechargeable battery 11 can be quickly charged in a short time of about several minutes, and the rechargeable battery 11 can be repeatedly charged simply by connecting the AC adapter 15, so that the speaker system 2 is used continuously. Even in such a case, music distributed cordlessly from the music player 1 can be continuously and stably reproduced without interrupting the use of the speaker system 2 for a long time.

  In addition, since the rechargeable battery 11 can be frequently charged, it is possible to use the rechargeable battery 11 having a small battery capacity, and the speaker system 2 can be reduced in size and weight and cost can be reduced. These can be realized by using the rechargeable battery 11 capable of rapid charging.

  Further, since the speaker system 2 can be configured cordlessly by using the rechargeable battery 11, by providing the speaker system 2 with a waterproof function, even if the music player 1 does not have a waterproof function, the speaker system 2 alone can be used. You can also listen to music by bringing it into a wet place such as a kitchen or bathroom.

  The system main body 2a is provided with a battery remaining amount display unit 6 for displaying the discharge state of the rechargeable battery 11, and the discharge state of the rechargeable battery 11 can be confirmed at a glance while using the speaker system 2. It can be avoided in advance that the remaining battery level of the rechargeable battery 11 becomes zero and the system becomes unusable.

(Modification 1)
In the above-described embodiment, the music player 1 has the wireless communication unit 1a. However, when the wireless communication function is not installed, for example, a dedicated wireless communication adapter 20 is prepared as shown in FIG. Then, the wireless communication adapter 20 may be connected to the headphone terminal 1b of the music player 1 via the cable 21. In this case, the wireless communication adapter 20 includes a short-range wireless communication interface such as Bluetooth, for example, and can modulate and transmit an audio signal reproduced by the music player 1.

  In this way, even a music player not equipped with a wireless communication function can be used in combination with the speaker system 2 described in the first embodiment.

(Modification 2)
In the above-described embodiment, the music player 1 has been described. However, the number of recent mobile phones equipped with a short-range wireless communication function such as Bluetooth is increasing. Therefore, if a two-way wireless communication system adapted to these wireless communication functions is incorporated in the speaker system 2, a hands-free call function of a mobile phone can also be installed. In this case, the system main body 2a of the speaker system 2 shown in FIG. 1B is provided with a microphone 22 on the front, and transmits the user's voice input from the microphone 22 to the mobile phone side.

  In this way, if the mobile phone has a wireless communication function and a music performance function, music is played using the cordless speaker system 2 of the present invention, and a hands-free call is made when an incoming call is received on the phone. It can be carried out. Further, since the speaker system 2 is cordless and independent of the mobile phone, the mobile phone can be used while being carried in the house while the mobile phone is still in the bag.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary. For example, in the above-described embodiment, the wireless communication units 1a and 13 that perform Bluetooth wireless communication have been described. However, any equivalent short-range communication may be used, and examples include UWB standards, infrared communication standards, and wireless LAN standards. Etc. can also be applied.

  In addition, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

The figure which shows schematic structure of the speaker system of the 1st Embodiment of this invention. The figure which shows the circuit structure of the speaker system of 1st Embodiment. The figure which shows schematic structure of the AC adapter connected to the speaker system of 1st Embodiment. The figure which shows schematic structure of the music player used for the modification 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Music player, 1a ... Wireless communication part 1b ... Headphone terminal, 2 ... Speaker system 2a ... System main body, 2b. 2c ... Speaker 3 ... Operation part 4 ... Power switch 5 ... AC adapter connection terminal 5a ... Positive side electrode 5b ... Negative side electrode 6 ... Battery remaining amount display part 11 ... Rechargeable battery 12 ... Control part 121 ... Speaker Driving means 122 ... Battery level monitoring means 13 ... Wireless communication part 14 ... Monitoring protection circuit 15 ... AC adapter 16 ... Charging part 17 ... AC / DC converter 18 ... Power cord 19 ... Plug 19a ... Positive electrode 19b ... Negative electrode 20 ... Wireless communication adapter, 21 ... Cable 22 ... Microphone

Claims (5)

A system main body that receives an audio signal wirelessly transmitted from the outside by a wireless communication unit, amplifies the received audio signal, and drives a speaker;
A speaker system comprising: a rechargeable battery that is provided inside the system body and that can be rapidly charged with a current of 10 C or more used as a power source for supplying power necessary for the operation of the system body. The speaker system according to claim 1, further comprising a charging unit, the charging unit including a charging unit that is electrically connectable to the system main body and charges the rechargeable battery in the connected state. . The speaker system according to claim 1, wherein the system main body includes a remaining battery capacity display unit that displays a remaining battery capacity of the rechargeable battery. 2. The speaker system according to claim 1, further comprising monitoring protection means for detecting at least one of overcharge, overdischarge and overcurrent of the rechargeable battery and stopping charging or discharging of the rechargeable battery. . 5. The speaker system according to claim 1, wherein the audio signal received by the wireless communication means is from a portable music player or mobile phone having wireless communication means.

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