JP4633533B2 - Portable radio - Google Patents

Description

  The present invention relates to a portable wireless device capable of reducing a local average SAR (Specific Absorption Rates) in a foldable mobile phone having a mechanism that can be opened and closed by connecting an upper housing and a lower housing with a hinge. It is.

In recent years, a technique for reducing a local average SAR (Specific Absorption Rate) is required for an antenna mounted on a portable wireless device (see, for example, Patent Document 1).
In general, when a portion where current is concentrated, such as an antenna feeding portion, is close to the human head, the local average SAR tends to increase. Therefore, in order to reduce the local average SAR when the antenna power feeding unit is close to the human head, it is necessary to separate the current concentrated on the power feeding unit from the human head as much as possible.
As such a method, there is a means for loading a ground wire in the vicinity of the antenna feeding portion shown in Patent Document 1. In Patent Document 1, a ground wire is arranged on the opposite side of the human head from the ground near the antenna power feeding unit with the housing interposed therebetween. The length of the ground wire is ¼ wavelength of the radio frequency, and the antenna current flowing through the ground resonates with the ground wire and also flows through the ground wire. Since the ground wire is arranged on the opposite side of the human head, the current in the vicinity of the power feeding flows to the ground wire, so that the current in the human head direction is reduced and the SAR is reduced.
Japanese Patent Application No. 2002-353719

  However, in the conventional portable wireless device, since the SAR reduction effect by the ground line can be obtained only at the resonance frequency of the ground line, in order to obtain the effect in a wide band, it is necessary to expand the band of the ground line. For this purpose, it is necessary to increase the distance between the ground line and the ground of the substrate, which hinders downsizing of the housing.

  The present invention has been made to solve the conventional problems, and particularly to provide a portable radio that can reduce the local average SAR and can be miniaturized in an antenna of a folding portable radio. Objective.

  The portable wireless device of the present invention is a portable wireless device in which a first housing and a second housing are rotatably connected by a hinge portion, and the first housing has an antenna element, The second casing includes a circuit board provided inside and having a ground pattern, and a power feeding element connected to a wireless circuit on the circuit board, and the hinge portion is made of a conductive metal. A first hinge portion and a second hinge portion; and a connecting portion that electrically connects the first hinge portion and the second hinge portion and rotatably supports the first hinge portion. Is attached to the first housing and is electrically connected to the end of the antenna element, and the second hinge portion is attached to the second housing and is connected to the ground pattern on the circuit board. Arranged at a predetermined interval and electrically connected to the feeding element. The antenna element, the hinge part and the power feeding element, and the ground pattern on the circuit board operate as a dipole antenna, and the positional relationship between the power feeding element and the hinge part in the thickness direction of the portable wireless device However, it has the structure which arrange | positions the said hinge part in the surface side close | similar to a head in a telephone call state, and arrange | positions the said electric power feeding element in the opposite surface side opposite to the said surface side.

  With this configuration, the feed element and the hinge portion operate as an upper element, and the ground of the circuit board operates as a dipole antenna as a whole, so that a high antenna gain can be obtained with the housing opened. Further, since the hinge portion is arranged on the surface side close to the head in a talking state and the feeding element is arranged on the opposite surface side opposite to the surface side, the antenna that flows in the hinge portion near the head in the talking state By reducing the current, the local average SAR can be reduced. In addition, since no ground wire is provided, the size can be reduced.

  The portable wireless device of the present invention has a configuration in which the power feeding element is connected to both ends of the second hinge portion in the casing short side direction.

  With this configuration, the feeding element is connected at both ends of the hinge portion in the short side direction of the hinge, so that two points of current concentration occur in the short side direction of the case of the hinge portion, and the current is dispersed. It will be. As a result, the current at the point where the current is concentrated becomes small, so that the local average SAR can be reduced.

  The present invention reduces the antenna current flowing in the hinge portion close to the head in a call state by disposing a hinge portion on the surface side close to the head in a call state and disposing a feeding element on the opposite side. Thus, it is possible to provide a portable radio having the effect of reducing the local average SAR and reducing the size because no ground line is provided.

Hereinafter, a portable wireless device according to an embodiment of the present invention will be described with reference to the drawings.
1A is a cross-sectional view of a portable wireless device according to an embodiment of the present invention, FIG. 1B is a front view, FIG. 2 is an enlarged perspective view of a power feeding unit of the portable wireless device, and FIG. 4B is a front view, FIG. 4 is an explanatory view of a talking state of the portable wireless device, FIG. 5 is an enlarged perspective view of the feeding portion in the conventional portable wireless device to be compared, and FIG. FIG. 7 is an explanatory diagram showing an antenna current distribution in a conventional portable wireless device to be compared.

In FIG. 1, a portable wireless device is obtained by connecting an upper housing 1 as a first housing and a lower housing 2 as a second housing by a hinge portion 3 so as to be rotatable. The housing 1 has a metal frame 7 serving as an antenna element, and the lower housing 2 is a power supply element connected to a circuit board 15 provided inside and having a ground pattern, and a wireless circuit 14 on the circuit board 15. Power supply sheet metal 11 and power supply pins 12.
The hinge portion 3 is configured to electrically connect the bearing 4 as the first hinge portion and the bearing 5 as the second hinge portion, and the bearing 4 and the bearing 5 which are made of a conductive metal and are rotatably supported. A rotating shaft 6 is provided as a connecting portion. The bearing 5 is attached to the upper housing 1 and is electrically connected to the end of the metal frame 7, and the bearing 4 is attached to the lower housing 2 and has a predetermined distance from the ground pattern on the circuit board 15. And are electrically connected to the power supply sheet metal 11.
Accordingly, the metal frame 7 as the antenna element, the hinge portion 3, the power supply sheet metal 11, the power supply pin 12, and the ground pattern on the circuit board 15 operate as a dipole antenna, and the power supply sheet metal 11 in the thickness direction of the portable wireless device The positional relationship with the hinge portion 3 is that the hinge portion 3 is arranged on the surface side close to the user's head in a call state, and the power supply sheet metal 11 is arranged on the opposite surface side.

  A rectangular frame-shaped metal frame 7 is provided on the inner surface of the upper housing 1, and a liquid crystal display unit 8 is provided in an opening provided in the center of the metal frame 7. In addition, on the upper side of the liquid crystal display unit 8 in the metal frame 7, a receiving unit 9 that emits sound is provided, and the user listens to the receiving unit 9 by listening to the ear.

The ground pattern disposed on the circuit board 15 is a conductor pattern disposed on almost the entire surface of the circuit board 15, and is a ground potential (ground potential) of the matching circuit 13 and the wireless circuit unit 14 configured on the circuit board 15. ).
The bearing 4 and the rotating shaft 6 are made of a conductive metal, and the bearing 4 is electrically connected to the bearing 5 through the rotating shaft 6. Therefore, the bearing 4 is electrically connected to the metal frame 7.
One end of the power supply sheet metal 11 is electrically connected to the bearing 4 of the hinge portion 3 by a metal screw 10, and the other end is connected to the matching circuit 13 via the power supply pin 12. The ground of the matching circuit 13 is connected so as to have the same potential as the ground of the circuit board 15.

With this configuration, the metal frame 7 and the hinge portion 3 operate as an upper element, and the ground of the circuit board 15 operates as a lower element as a whole as a dipole antenna.
As a result, a high antenna gain can be obtained with the housing opened.

Next, the antenna feeding structure will be described in detail.
FIG. 2 is an enlarged perspective view of the vicinity of the power feeding portion, and FIG. 3 is a cross-sectional view and a front view showing the attachment of the power feeding sheet metal.
As shown in FIGS. 2 and 3, the power supply sheet metal 11 has an L-shaped cross section when viewed from the side of the housing. For example, the dimension is such that the length L1 in the width direction is 45 mm and the length L2 in the longitudinal direction is 10 mm and the length L3 in the thickness direction are 8 mm. Further, the connecting portion with the bearing 4 is bifurcated, and the power feeding sheet metal 11 is connected to each of the bearings 4 and 4 arranged in the direction of the short side of the casing to be fed.
The power supply sheet metal 11 and the matching circuit 13 are connected by power supply pins 12 provided on the circuit board 15. Further, the height L4 of the power supply pin 12 from the substrate is, for example, 6 mm. Therefore, the power feeding sheet metal 11 is fed from the lower substrate 15 where the matching circuit 13 is provided at a position protruding 6 mm to the opposite side of the hinge portion 3 in the thickness direction.

The SAR reduction effect in the portable wireless device having such a structure will be described. Here, the radio frequency is set to 900 MHz, for example.
FIG. 4 shows a state in which the user is talking with the case opened. The user makes a call by placing the earpiece 17 provided on the upper housing 1 against the ear 17. From this figure, it can be seen that the hinge portion 3 is closer to the human head 16 than the circuit board 15 with the matching circuit 13. Since it is known that the local SAR increases as the antenna current flowing near the head 16 increases, the local SAR increases as the antenna current flowing through the hinge 3 close to the head 16 increases. . In other words, if the antenna current flowing through the hinge portion 3 can be reduced, the local SAR can be reduced.

Here, for comparison, a power supply structure of a portable wireless device having a conventional configuration will be described.
FIG. 5 shows an enlarged view of a power feeding unit of a portable wireless device having a conventional configuration. In addition, the same code | symbol is attached | subjected to the site | part which is common in the portable radio | wireless machine which concerns on this invention mentioned above, and the overlapping description is abbreviate | omitted. As shown in FIG. 5, the bearing 4, which is the first hinge portion of the hinge portion 3, and the circuit board 15 on which the matching circuit 13 is mounted are directly connected by a power supply metal plate 21 at a substantially shortest distance to supply power. For this reason, the element length of the power supply sheet metal 21 is, for example, 10 mm. Points other than the power feeding structure are the same as in this embodiment.

FIG. 6 shows the antenna current distribution of the portable wireless device of this embodiment, and FIG. 7 shows the antenna current distribution of the portable wireless device of the conventional configuration shown in FIG.
The maximum point of each antenna current is the point (A) and the point (C). In both portable wireless devices, the maximum point of the antenna current is the feeding point, that is, the connection point between the matching circuit 13 and the feeding metal plates 11 and 21. Yes. However, the current flowing through the hinge portion 3 is smaller in the present embodiment than the comparison between the points (B) and (D) indicating the current of the hinge portion 3. This is because the current path from the power supply point to the hinge portion 3 is as short as 10 mm in the power supply sheet metal 21 in the conventional configuration. This is because the hinge portion 3 is far from the feeding point.

As described above, since the local SAR can be reduced by reducing the antenna current flowing in the hinge portion 3 near the head portion 16 in a call state, the present embodiment has a hinge portion as compared with a portable wireless device having a conventional configuration. The local SAR can be reduced by reducing the current flowing through the circuit 3.
Further, as shown in FIG. 4, since the power supply sheet metal 11 is farther from the head 16 than the hinge part 3 in a call state, the local SAR is not increased due to the antenna current flowing through the power supply sheet metal 11.

  In the present embodiment, since the power feeding sheet metal 11 is connected at both ends of the hinge 3 on the short side of the casing, two points of current concentration occur in the short side of the casing of the hinge 3. , Can disperse current. That is, the current at the point where the current is concentrated is smaller than the structure in which power is supplied to only one of the bearings as in the conventional portable radio shown in FIG. In general, the local SAR increases as the current concentrates. However, in the structure in which power is supplied to both ends of the hinge portion as in the present embodiment, the current is dispersed and the current is reduced, so the local average SAR can be reduced.

In the above description, a plate-like member having a width L1 of 45 mm is exemplified as the power supply sheet metal 11. However, even if the sheet metal 11 is a linear element having a width L1 of about 2 mm, the power supply sheet metal 11 is a hinge. If it is farther from the head 16 than the part 3, the same SAR reduction effect can be obtained. However, if the cross-sectional area of the power supply sheet metal 11 is reduced, the effective volume of the antenna is reduced and the bandwidth is narrowed. Therefore, it is desirable to configure the power supply sheet metal 11 to have a cross-sectional area as large as possible.
Further, as compared with the SAR reduction means for loading the ground wire, there is an advantage that the SAR reduction effect can be obtained in a wide frequency band because it does not depend on the resonance frequency of the ground wire. Further, since an additional part such as a ground wire is unnecessary, the housing can be reduced in size.

  As described above, the portable wireless device according to the present invention arranges the hinge part on the surface side close to the head in the call state and arranges the power feeding element on the opposite side, thereby providing the head in the call state. The antenna current flowing in the nearby hinge portion can be reduced to reduce the local average SAR, and the ground wire is not provided, so that the size can be reduced. It is useful as a portable wireless device that can reduce the local average SAR in a foldable mobile phone having a mechanism that can be connected and opened.

(A) is sectional drawing of the portable radio | wireless machine concerning embodiment of this invention, (B) is a front view. It is an expansion perspective view of the electric power feeding part of a portable radio. (A) is an expanded sectional view of the power feeding unit of the portable wireless device, and (B) is a front view. It is explanatory drawing of the telephone call state of a portable radio. It is an expansion perspective view of the electric power feeding part in the conventional portable radio device to compare. It is explanatory drawing which shows distribution of the antenna current in this embodiment. It is explanatory drawing which shows distribution of the antenna current in the conventional portable radio | wireless machine to compare.

Explanation of symbols

1 Upper housing (first housing)
2 Lower housing (second housing)
3 Hinge part 4 Bearing (first hinge part)
5 Bearing (second hinge part)
6 Rotating shaft (connecting part)
7 Metal frame (antenna element)
11 Feeding sheet metal (feeding element)
12 Feeding pin (feeding element)
14 wireless circuit 15 circuit board

Claims (2)

A portable wireless device in which a first housing and a second housing are rotatably connected by a hinge part,
The first housing has an antenna element;
The second housing includes a circuit board provided inside and having a ground pattern, and a power feeding element connected to a wireless circuit on the circuit board,
The hinge part is a first hinge part and a second hinge part made of conductive metal, and a connection for electrically connecting the first hinge part and the second hinge part and rotatably supporting the hinge part. And
The first hinge portion is attached to the second casing, is disposed at a predetermined interval from a ground pattern on the circuit board, and is electrically connected to the power feeding element. The second hinge portion Is attached to the first housing and is electrically connected to the end of the antenna element ,
The antenna element, the hinge part and the power feeding element, and the ground pattern on the circuit board operate as a dipole antenna, and the positional relationship between the power feeding element and the hinge part in the thickness direction of the portable wireless device is a call. A portable wireless device in which the hinge portion is arranged on the surface side close to the head in the state, and the feeding element is arranged on the opposite surface side opposite to the surface side. The portable wireless device according to claim 1 , wherein the power feeding element is connected to both ends of the first hinge portion in a casing short side direction.

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