JP2012124676A - Portable electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable electronic apparatus having an enhanced antenna radiation efficiency for eliminating the cause of antenna radiation efficiency degradation because of heat loss occurred in any part of an emitter consisting of an antenna and a battery when the portable electronic apparatus battery causes resonance.SOLUTION: A portable electronic apparatus of FIG.1 is provided to settle the above problem. The portable electronic apparatus of FIG.1 includes: an antenna; a power supply circuit for supplying operation voltage to the antenna; and a battery for supplying electric power to a power supply circuit. In addition, a resonance circuit synchronizing with a communication frequency of the antenna is inserted within a connection part of any one of a first connection part between a battery positive electrode and a power supply circuit or a second connection part between a battery negative electrode and a circuit ground. Even if the battery causes unnecessary resonance, the resonance circuit cuts off the high-frequency current. At the same time, the flow of high-frequency current into a battery generated by the antenna operation is also cut off, to inhibit the heat loss of battery itself.

Description

  The present invention relates to a portable electronic device. In particular, the present invention relates to a portable electronic device including an antenna and a battery.

  In recent years, portable electronic devices such as mobile phones, PHS (Personal Handyphone System), and PDA (Personal Digital Assistants) have become widespread and highly functional. A single portable electronic device needs to support different communication methods such as WCDMA (Wideband Code Multiple Access) and GSM (Global System for Mobile communications), Bluetooth (registered trademark), WLAN The current situation is that there is a strong demand for wireless communication such as

  As described above, the number of antennas inside the portable electronic device is increasing due to diversification of communication methods and increase in various communication applications. On the other hand, when the number of antennas increases and the communication frequency increases accordingly, the influence of each antenna on other antennas becomes very complex, and the influence between each antenna is necessary to satisfy the performance required for portable electronic devices. It becomes a very difficult situation to reduce. However, even if the number of antennas increases, the performance and quality required for portable electronic devices such as communication quality and usability are not allowed.

  In addition, the portable electronic device is a device that is always carried around, and the portable electronic device requires a battery such as a dry battery or a rechargeable battery. And this battery itself may be influenced by the circuit and ground inside a portable electronic device, and may cause resonance at a specific frequency. If the resonance in the battery is in the vicinity of the communication frequency used by the portable electronic device, the radiation efficiency of the antenna may be degraded.

  Therefore, Patent Document 1 discloses a technique for shifting the resonance frequency of a battery pack by bringing a metal protrusion into contact with a battery cell and avoiding an influence on antenna characteristics due to the battery resonating.

  Further, in Patent Document 2, when resonance occurs between the internal wiring in the charger of the mobile phone and the mobile phone, a resonance circuit is inserted between the ground and the influence of resonance generated between the internal wiring and the mobile phone. A technique for reducing the above is disclosed.

  Furthermore, Patent Document 3 discloses a technique for designing an antenna and a battery terminal as a single unit to reduce subsequent design changes.

JP 2009-193873 A Japanese Patent Laying-Open No. 2005-086939 JP 2009-194427 A

  The following analysis has been made from the viewpoint of the present invention.

  As described above, the number of antennas mounted on portable electronic devices is increasing. Then, the types of communication frequencies also increase, and when the battery itself resonates due to the influence of the ground inside the portable electronic device, the possibility of overlapping with these communication frequency bands is greatly increased, and the antenna radiation efficiency is degraded. Concerns increase. Accordingly, it is required to reduce the influence of resonance in the battery itself on the antenna radiation efficiency.

  At this time, as disclosed in Patent Document 3, if the battery terminal is integrated with other components such as an antenna, structural restrictions increase, and the degree of freedom in designing a portable electronic device is reduced. There is a problem. Further, in the technique disclosed in Patent Document 3, the influence of the battery itself on the antenna is not considered, and it is difficult to avoid a decrease in antenna efficiency due to the influence of the battery itself. This is because the battery is electrically integrated with the antenna and must be avoided by physical adjustment including the antenna.

  Here, the antenna radiation efficiency is represented by the ratio of the radiated power and the input power. The following two reasons are conceivable as causes for reducing the antenna radiation efficiency.

  The first reason is the presence of power reflected at the input end of the antenna.

  The second reason is the presence of heat loss caused by radiators and insulators. When the battery included in the portable electronic device or the wiring of the charger as disclosed in Patent Document 2 resonates at a specific frequency, the battery, the wiring, and the antenna are integrated to form a radiator. If heat loss occurs in a part of this radiator, energy that is originally used as radiated power is lost, so that antenna radiation efficiency decreases.

  In addition, even when the battery itself does not resonate, while the antenna is operating and performing communication, that is, while the antenna radiates high frequency energy as electromagnetic waves, A high frequency current may flow through the negative terminal. When high-frequency current flows through the positive electrode terminal and the negative electrode terminal of the battery, heat loss occurs in the insulator and the organic solvent used inside the battery. In this case as well, energy supplied from the battery is lost, causing a reduction in antenna radiation efficiency.

  In this way, the antenna radiation efficiency is affected by both the heat loss caused by the resonance of the battery itself and the heat loss caused by the high-frequency current flowing in the positive electrode terminal and the negative electrode terminal of the battery. .

  As described above, there are problems to be solved in the prior art.

  In one aspect of the present invention, a portable electronic device in which the antenna radiation efficiency is improved by suppressing the resonance of the battery itself and the influence of the high-frequency current flowing through the battery is desired.

  According to a first aspect of the present invention, an antenna, a power supply circuit that supplies an operating voltage to the antenna, a battery that is connected to the power supply circuit and supplies power to the power supply circuit, and the antenna Synchronized with the communication frequency, inserted between the first connection between the positive terminal of the battery and the power circuit, or the second connection between the negative terminal of the battery and circuit ground. A portable electronic device comprising a resonance circuit is provided.

  According to each aspect of the present invention, there is provided a portable electronic device in which the resonance of the battery itself and the influence of the high-frequency current flowing through the battery are suppressed, and the antenna radiation efficiency is improved.

It is a figure for demonstrating the outline | summary of this invention. 1 is a perspective view showing an overview of a portable electronic device according to a first embodiment of the present invention. It is the block diagram which showed the internal structure of the portable electronic device which concerns on 1st Embodiment. FIG. 4 is a diagram illustrating a configuration example of a resonance circuit illustrated in FIG. 3. FIG. 4 is a diagram illustrating a configuration example of a resonance circuit illustrated in FIG. 3. It is a figure which shows the structure of the portable electronic device at the time of performing verification by a real machine. It is a figure which shows an example of the verification result of the antenna radiation efficiency in the structure shown in FIG.

  First, the outline of the present invention will be described with reference to FIG. Note that the reference numerals of the drawings attached to this summary are attached to the respective elements for convenience as an example for facilitating understanding, and are not intended to limit the present invention to the illustrated embodiment.

  As described above, when the battery of the portable electronic device resonates, heat loss occurs in any part of the radiator composed of the antenna and the battery. In addition, when the portable electronic device performs a communication operation, a high-frequency current flows through the positive electrode terminal and the negative electrode terminal of the battery, causing heat loss. Both of these cause a reduction in antenna radiation efficiency.

  Therefore, the portable electronic device shown in FIG. 1 is provided. The portable electronic device shown in FIG. 1 includes an antenna, a power supply circuit that supplies an operating voltage to the antenna, and a battery that supplies power to the power supply circuit. Further, a resonant circuit that is tuned to the communication frequency of the antenna is inserted into either the first connection between the battery positive terminal and the power supply circuit, or the second connection between the battery negative terminal and the circuit ground. . Even if the battery causes unnecessary resonance, the high-frequency current flowing from the battery is cut off by the action of the resonance circuit. At the same time, the generation of high-frequency current caused by the operation of the antenna is suppressed, and the heat loss of the battery itself is suppressed. As a result, the antenna radiation efficiency can be improved.

[First Embodiment]
Next, the first embodiment of the present invention will be described in more detail with reference to the drawings. FIG. 2 is a perspective view showing an overview of the portable electronic device 1 according to the present embodiment. The portable electronic device 1 includes an antenna 10. In the following description, it is assumed that the antenna 10 operates as an antenna for Bluetooth (registered trademark). Note that the Bluetooth (registered trademark) antenna is disposed inside the portable electronic device 1 and is often not visible from the outside.

  FIG. 3 is a block diagram showing the internal configuration of the portable electronic device 1. The portable electronic device 1 includes an antenna 10, a transmission / reception circuit 20, a battery connection terminal 30, a power supply circuit 40, an overvoltage protection circuit 50, a temperature detection circuit 60, a remaining amount display circuit 70, and a resonance circuit 80. It is composed of

  The antenna 10 is used as an antenna for realizing wireless communication by Bluetooth (registered trademark), and operates in a band of about 2.4 GHz.

  The transmission / reception circuit 20 is connected to the antenna 10 and the power supply circuit 40, and realizes wireless communication by Bluetooth (registered trademark).

  The battery connection terminal 30 includes a positive terminal 31, a negative terminal 32, and a control terminal 33. In the description of the present embodiment, the control terminal 33 is described as one, but the present invention is not limited to this. A plurality of control terminals may be provided. These terminals are connected to the power supply circuit 40, and the negative terminal 32 is grounded to the ground of the circuit board. The battery 34 connected to the battery connection terminal 30 is a lithium ion rechargeable battery and is a power supply source of the portable electronic device 1. The battery 34 is disposed very close to the antenna 10.

  The battery connection terminal 30 is structurally and electrically independent from the battery 34 attached to the portable electronic device 1 and the circuit board other than the circuit board of the portable electronic device 1. The structurally independent means that it is not fixed to the casing of the portable electronic device 1, and the electrically independent means that there is no electrical connection path other than the circuit board. Means that. Accordingly, the degree of freedom in mounting the battery connection terminal 30 is increased, and the design man-hour and cost can be reduced.

  The power supply circuit 40 is connected to the battery connection terminal 30 and supplies power to each part of the portable electronic device using the battery 34 as a power supply source.

  The overvoltage protection circuit 50 is a circuit for protecting the battery 34 from overcharging by cutting off the current supplied to the battery 34 when the voltage of the battery 34 exceeds the voltage at the time of full charge.

  The temperature detection circuit 60 is a circuit for detecting a temperature change of the battery 34.

  The remaining amount display circuit 70 is a circuit for monitoring the remaining amount of the battery 34 and notifying the user of a decrease in the remaining amount, and prevents sudden loss of power to the portable electronic device 1.

  The overvoltage protection circuit 50 and the remaining amount display circuit 70 are connected to the positive terminal 31 and the negative terminal 32 of the battery connection terminal 30, and the temperature detection circuit 60 is connected to the negative terminal 32 and the control terminal 33.

  The resonance circuit 80 is connected between the negative electrode terminal 32 of the battery connection terminal 30 and the ground ground of the circuit board (corresponding to the second connection described above). The resonance circuit 80 is connected between the positive electrode terminal 31 of the battery connection terminal 30 and the power supply circuit 40 (the first connection described above), in addition to between the ground connection of the negative electrode terminal 32 circuit board (second connection), or It can be connected between the control terminal 33 of the battery connection terminal 30 and the power supply circuit 40 (hereinafter referred to as a third connection). Furthermore, the resonance circuit 80 can be connected not only to one place of the first connection, the second connection, and the third connection, but also by a combination thereof. For example, it can be a combination of a first connection and a second connection.

  Here, a specific circuit used for the resonance circuit 80 will be described. The resonance circuit 80 may be any of the resonance circuits shown in FIG. 4 or FIG. FIG. 4 is a diagram illustrating a configuration of the resonance circuit 801. The resonance circuit 801 has a configuration in which a capacitor C1 and a coil L1 are connected in series and grounded. FIG. 5 is a diagram showing the configuration of the resonance circuit 802. The resonance circuit 802 is configured to connect the capacitor C2 and the coil L2 in parallel.

  Next, the role of the resonance circuit 80 when the mobile electronic device 1 performs wireless communication by Bluetooth (registered trademark) using the antenna 10 will be described. When the portable electronic device 1 performs transmission / reception, the battery 34 resonates due to the electromagnetic wave radiated from the antenna and the high-frequency current transmitted through the circuit board. The resonance frequency at that time is 2.4 GHz.

  As described above, when the resonance circuit 80 having a cutoff frequency of 2.4 GHz is inserted into any of the first connection, the second connection, and the third connection in a state where the battery 34 is causing unnecessary resonance. The effect of battery resonance on antenna radiation efficiency is reduced. That is, the impedance at the cutoff frequency of the resonance circuit 80 is very high, and the high-frequency current (2.4 GHz) generated by the resonance of the battery 34 is cut off at the resonance circuit 80 and passes through the resonance circuit 80 to the power supply circuit 40. There is no flow. Then, since the battery 34 and the antenna 10 form one radiator, the heat loss generated in any of the radiators can be reduced and the antenna radiation efficiency can be improved.

  At the same time, by inserting the resonant circuit 80 having a cutoff frequency of 2.4 GHz into any of the first connection, the second connection, and the third connection, the high-frequency current radiated from the antenna and transmitted through the circuit board is also reduced. Will be blocked. Then, the resonance of the battery itself is suppressed, and the heat loss caused by the battery insulator or the like is also reduced. Due to these combined effects, the radiation efficiency of the antenna 10 can be improved.

  6 shows a case where the temperature detection circuit 60 is removed from the portable electronic device 1 shown in FIG. 3 and the resonance circuit 801 is inserted as the resonance circuit 80 between the control terminal 33 and the power supply circuit 40 (third connection). FIG. The effectiveness of the resonant circuit 80 was verified using the portable electronic device 1a shown in FIG.

  FIG. 7 is a diagram illustrating an example of the antenna radiation efficiency when the resonant circuit 80 is removed from the portable electronic device 1a and the result of measuring the antenna radiation efficiency by inserting the resonant circuit 80. The antenna efficiency is measured at the time of wireless communication using Bluetooth (registered trademark), and the cutoff frequency of the resonance circuit 80 is 2.4 GHz. In FIG. 7, the vertical axis represents the antenna radiation efficiency, and the horizontal axis represents the communication frequency of the antenna 10. 7 indicates the antenna radiation efficiency when the resonance circuit 80 does not exist, and ■ indicates the antenna radiation efficiency when the resonance circuit 80 exists.

  From FIG. 7, it can be seen that the antenna radiation efficiency at 2.4 GHz is improved by 1 dB despite the completely same configuration except for the presence or absence of the resonance circuit 80. At the same time, it can be seen that the antenna efficiency is superior in the case where the resonance circuit 80 is present even at 2.484 GHz that deviates from the cutoff frequency of 2.4 GHz. This can be considered that even if the battery itself does not resonate, the resonance circuit 80 avoids the heat loss of the battery 34 itself and contributes to the improvement of the antenna radiation efficiency.

  As described above, in a portable electronic device including an antenna and a battery, by inserting a resonance circuit into the connection terminal of the battery, it is possible to avoid the influence due to resonance by the battery and improve the antenna radiation efficiency.

  Here, the influence of battery resonance greatly depends on the distance and wiring between the battery and the antenna. Furthermore, the frequency at which the resonance of the battery occurs depends on the positive terminal and the negative terminal of the battery. These facts mean that it is difficult to design a portable electronic device in consideration of battery resonance in advance.

  Even if it is known in advance that the resonance of the battery will affect the antenna radiation efficiency, the effect of the resonance of the battery will not be known unless it is verified on the actual device. It was necessary to adjust. Even if physical measures are not required, if the connection points of the resonance circuit are limited, the connection points are not always the optimal connection points, and sufficient performance improvements are made. It is also possible that it is not.

  However, as in the portable electronic device 1 described in the present embodiment, if the point where the resonance circuit is connected can be connected not only to the positive terminal or the negative terminal of the battery but also to the control terminal, such a case. The problem is solved. That is, if a circuit pattern of a portable electronic device is created so that resonance circuits can be inserted at a plurality of points, it is only necessary to insert resonance circuits only at the most effective points after completion of the actual device. This contributes to a reduction in design man-hours and costs in product development.

  In the technique disclosed in Patent Document 1, a part of a metal tab constituting the battery pack is brought into contact with the cell, thereby changing the resonance frequency by the battery and avoiding the influence on the antenna characteristics. However, whether or not the battery is resonating at a frequency that affects the antenna characteristics is specified after the battery is actually connected to the portable electronic device. There is a high possibility that the shape change is necessary, and there is a problem that the design man-hour increases. Also in this regard, the design man-hour does not increase because the circuit constant on the circuit board is only changed in this embodiment.

  Furthermore, in the portable electronic device 1 according to the present embodiment, the battery connection terminal is independent of the antenna. In particular, if the battery 34 is a battery pack, a battery pack whose cell surface is not in contact with another metal is used. As a result, it is not necessary to perform physical adjustment of the antenna itself in order to avoid the influence of the battery, and the design man-hour and cost can be reduced.

  Even when the battery connection terminal has no control terminal, the same effect can be obtained by inserting a resonant circuit between the positive terminal and the power supply circuit or between the negative terminal and the circuit board ground. Further, not only a single-band antenna such as Bluetooth (registered trademark) but also a multi-band antenna corresponding to other frequency bands, the same effect can be obtained, and a portable electronic device equipped with two or more antennas The same applies to. For example, when a dual-band antenna is installed instead of a single-band, in order to avoid the influence in a certain frequency band, a resonance circuit is inserted in the first connection to avoid the influence in another frequency band. Therefore, it is possible to insert a different resonant circuit in the second connection. Furthermore, even in a portable electronic device in which two or more batteries are mounted, the same effect can be obtained if a resonance circuit is inserted into each terminal of each battery.

  A part or all of the above embodiments can be described as in the following supplementary notes, but is not limited thereto.

  (Supplementary Note 1) An antenna, a power supply circuit that supplies an operating voltage to the antenna, a battery that is connected to the power supply circuit and supplies power to the power supply circuit, and a communication frequency of the antenna, A portable circuit comprising: a resonance circuit inserted between a first connection between a positive electrode terminal of a battery and the power supply circuit, or a second connection between the negative electrode terminal of the battery and a circuit ground. Electronics.

  (Additional remark 2) Furthermore, when the battery includes a control terminal, and the control terminal and the power supply circuit are connected, the resonance circuit includes the first connection, the second connection, or the control. A portable electronic device inserted between any one of a third connection between a terminal and the power supply circuit.

  (Additional remark 3) The said battery and the said power supply circuit are connected via the battery connection terminal, and the said battery connection terminal is a portable electronic device which is contacting only the said battery and a circuit board.

  (Additional remark 4) A portable electronic device provided with two or more said resonance circuits.

  (Supplementary note 5) A portable electronic device further comprising a plurality of the antennas, wherein the plurality of resonance circuits include ones that are tuned to the communication frequency of each antenna.

  (Additional remark 6) The said battery is a portable electronic device which is a battery pack whose cell surface is not in contact with other metals.

  (Additional remark 7) The said battery is a portable electronic device which is either a dry cell or a rechargeable battery.

  (Appendix 8) The resonant circuit is a portable electronic device in which a capacitor and a coil are connected in parallel.

  (Supplementary note 9) The resonant circuit is a portable electronic device in which a capacitor and a coil are connected in series and one end is grounded.

  (Additional remark 10) The said antenna is a portable electronic device which is a multiband antenna.

  (Additional remark 11) The said antenna is a portable electronic device which is a single band antenna.

  (Additional remark 12) The said several antenna is a portable electronic device which is either a single band antenna or a multiband antenna.

  It should be noted that the disclosures of the above patent documents and the like are incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiment can be changed and adjusted based on the basic technical concept. Various combinations and selections of various disclosed elements are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea. For example, the battery is not limited to a lithium ion rechargeable battery, and may be other types of batteries.

DESCRIPTION OF SYMBOLS 1, 1a Portable electronic device 10 Antenna 20 Transmission / reception circuit 30 Battery connection terminal 31 Positive electrode terminal 32 Negative electrode terminal 33 Control terminal 34 Battery 40 Power supply circuit 50 Overvoltage protection circuit 60 Temperature detection circuit 70 Remaining amount display circuits 80, 801, 802 Resonance Circuit C1, C2 Capacitor L1, L2 Coil

Claims (10)

An antenna,
A power supply circuit for supplying an operating voltage to the antenna;
A battery connected to the power supply circuit and supplying power to the power supply circuit;
Between the connection of either the first connection between the positive terminal of the battery and the power circuit, or the second connection between the negative terminal of the battery and circuit ground, in tune with the communication frequency of the antenna A resonant circuit to be inserted;
A portable electronic device comprising:   Further, when the battery includes a control terminal, and the control terminal and the power supply circuit are connected, the resonance circuit includes the first connection, the second connection, or the control terminal and the power supply. The portable electronic device of claim 1, wherein the portable electronic device is inserted between any one of the third connections between the circuits.   The portable electronic device according to claim 1 or 2, wherein the battery and the power supply circuit are connected via a battery connection terminal, and the battery connection terminal is in contact with only the battery and the circuit board.   The portable electronic device according to any one of claims 1 to 3, comprising a plurality of the resonance circuits.   The portable electronic device according to claim 4, further comprising a plurality of the antennas, wherein the plurality of resonance circuits include ones that are tuned to a communication frequency of each antenna.   The portable electronic device according to any one of claims 1 to 5, wherein the battery is a battery pack whose cell surface is not in contact with another metal.   The portable electronic device according to claim 1, wherein the battery is either a dry battery or a rechargeable battery.   The portable electronic device according to claim 1, wherein the resonance circuit is a capacitor and a coil connected in parallel.   The portable electronic device according to any one of claims 1 to 7, wherein the resonance circuit is formed by connecting a capacitor and a coil in series and grounding one end.   The portable electronic device according to claim 1, wherein the antenna is a multiband antenna.

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