JP4814804B2 - Mobile radio communication device - Google Patents

Description

  The present invention relates to a mobile communication device such as a mobile phone, and more particularly to a portable wireless communication device that reduces the influence of a human body during a call.

  If the antenna mounted on the mobile phone is placed at a position close to the human head when using a phone call, there is a concern about deterioration of the antenna characteristics due to the human head or the influence on the human head caused by electromagnetic waves radiated from the antenna. The As a countermeasure against this problem, there is a conventional technique in which a shielding plate made of a metal plate or the like is disposed at a position where the antenna is shielded from the human head when the mobile phone is held in a calling state (Patent Document 1). .

  FIG. 4A is a cross-sectional view showing the configuration of such a conventional mobile phone, and FIG. 4B is a diagram for explaining the use state of the call. As shown in FIG. 4 a, the conventional mobile phone includes a resin casing 41, a circuit board 42, an antenna 43 mounted on the receiver side end of the circuit board 42, and a shielding plate 44. The housing 41 includes a receiver 45, a transmitter 46, and operation keys 47. The antenna 43 is connected to the high-frequency radio circuit 48 mounted on the substrate 42 by a feed line. The shielding plate 44 is grounded to the circuit board 42.

  According to this structure, as shown in FIG. 4b, even when the mobile phone is held in a call use state, since the shielding plate exists between the adjacent human head 31 and the antenna, the antenna is the human head 31. As a result, the deterioration of the antenna characteristics is reduced, and at the same time, the effect of the human head 31 from the antenna is also reduced.

Japanese Patent Laid-Open No. 11-31909

  However, considering the recent thinning and miniaturization of mobile phones, it is difficult to make the distance between the antenna and the shielding plate sufficiently large with respect to the wavelength in the configuration as in the conventional technology described above. Therefore, although the arrangement of the shielding plate as in the prior art has the effect of reducing the deterioration in the call usage state and reducing the influence on the human body, the antenna is not used in the call usage state and the human body is not in proximity to the antenna. Due to the proximity of the ground metal to, the electrical volume of the antenna is reduced, which causes a problem that the antenna characteristics deteriorate. In order to solve this problem, it is necessary to increase the volume of the antenna, and there is a problem that it is contrary to the recent demand for thinner and smaller mobile phones.

  The present invention has been made in view of such problems, and reduces the influence of the human head on the antenna characteristics when using a telephone call, and reduces the influence of the antenna radiated radio wave on the human head. An object of the present invention is to provide a mobile radio communication device that suppresses deterioration of antenna characteristics due to proximity of a shielding plate metal to an antenna when it is not close to the antenna.

Radio of the present invention includes a circuit board, and an antenna connected to the radio circuit, and a metal plate which is not electrically connected to the ground pattern of the circuit board, and a conductive connection electrically conductive component and the ground pattern, wherein The metal plate is disposed between the antenna and the receiver, and the metal plate and the conductive component are capacitively coupled when a human head is close to the receiver . A housing for housing the circuit board may be provided, and a gap between the metal plate and the conductive component may be near the surface on the receiver side of the housing.

A housing for accommodating the prior SL circuit board, and a display panel, the previous SL display panel and the receiver unit are disposed on a surface of the housing, wherein the metal plate and the conductive parts with a gap And, it may be arranged in substantially the same plane as the display surface of the display panel.

  The resonance wavelength of the metal plate may be substantially the same as the resonance wavelength of the antenna. As a result, in a state where the human head is not in proximity, the metal plate and the antenna cause double resonance, and it is possible to obtain broadband antenna characteristics.

  The resonance wavelength of the metal plate may be longer than the resonance wavelength of the antenna. Thereby, in a state where the human head is not close, the metal plate can be operated as a reflector for the antenna. Since the metal plate is disposed on the front side of the mobile radio communication terminal relative to the antenna, the radiation pattern of the antenna can be directed to the back side of the mobile radio communication terminal.

  The resonance wavelength of the metal plate may be shorter than the resonance wavelength of the antenna. As a result, the metal plate can be operated as a director for the antenna when the human head is not in proximity. Since the metal plate is arranged on the surface side of the mobile radio communication terminal with respect to the antenna, the radiation pattern of the antenna can be directed in the forward direction of the terminal.

  You may provide a slit in the said metal plate. Thus, in a state where the human head is not in proximity, the metal plate can have a lower resonance wavelength within the area where the metal plate can be installed.

The metal plate has a first metal piece and a second metal piece, and by switching a conduction state between the first metal piece and the second metal piece, the electrical length of the metal plate is You may make it switchable whether it is longer or shorter than the half wavelength in the resonant frequency of an antenna.

The metal plate includes a first metal piece and a second metal piece, and the first metal piece and the second metal piece are connected via a filter element, and the filter element is connected to the wireless element. A part of the frequency used by the machine may be transmitted and the other part may be blocked.

  According to the present invention, when using a telephone call, the influence of the human head on the antenna characteristics is reduced and the influence of the antenna radiated radio wave on the human head is reduced. When the human body is not close to the antenna, the shielding plate metal is attached to the antenna. A mobile radio communication device that suppresses deterioration of antenna characteristics due to proximity is realized.

  First, a first embodiment of the present invention will be described. FIG. 1a is a side view of a part of the mobile phone terminal of the present embodiment, and FIG. 1b is a front view. The mobile phone of the present embodiment includes an upper housing 1A and a lower housing 1B that are foldably connected via a hinge 1C.

  The upper casing 1A includes a receiver 5, a liquid crystal display panel 9, a liquid crystal holder 10 that reinforces the liquid crystal display panel 9, a circuit board 2, a high-frequency wireless circuit 8 mounted on the circuit board, and a circuit board 2. The antenna 3 and the metal plate 4 mounted above are provided. The liquid crystal holder 10 is made of a conductive metal such as a magnesium alloy so as to surround the periphery of the liquid crystal display panel 9 excluding the display surface. The liquid crystal holder 10 and the ground pattern of the circuit board 2 are conductively connected by metal springs 11 at a plurality of locations. The receiver 5 is disposed at the upper end of the upper housing 1A. The antenna 3 is a 1 / 4λ inverted L antenna system for receiving GPS (Global Positioning System), and is mounted on the upper end of the circuit board 2. The high frequency radio circuit 8 is a GPS receiving circuit, and is electrically connected to the antenna 3 through a transmission line.

  As shown in FIG. 5, the ground pattern of the circuit board 2 is a pattern of a ground potential at an arbitrary place other than the antenna mounting position on the circuit board 2. It does not exist as a separate body from the circuit board 2. Actually, since the parts are mounted on the surface layer, the entire surface does not become the ground potential.

  The metal plate 4 is disposed at the inner upper end of the upper housing 1A, substantially parallel to the circuit board 2 and in the same plane as the display surface of the liquid crystal display panel 9, with a gap from the liquid crystal holder 10. 2 and the liquid crystal holder 10 are not conductively connected. The electrical length of the metal plate 4 is approximately a half wavelength at the resonance frequency of the antenna 3. The lower housing 1B includes a transmitter 6 and operation keys 7, and has a circuit board (not shown) inside.

  FIG. 1c is a diagram showing a call use state of the mobile phone terminal of the present embodiment. As shown in this figure, when the human ear is applied to the receiver 5, the human head 31 comes close to the antenna 3, but the metal plate 4 is positioned between the human head 31 and the antenna 3. In addition, the metal plate 4 operates as a reflecting plate by capacitively coupling the liquid crystal holder 10 and the ground pattern of the circuit board 2 via the human head 31. Thereby, compared with the case where the metal plate 4 does not exist, the influence which the human body head 31 has on the antenna 3 is reduced. On the other hand, when the telephone is not in use and the human body is not in proximity to the antenna 3 and the metal plate 4, the metal 4 is in an electrically floating, non-powered and ungrounded state. Therefore, an image current having a phase opposite to that of the antenna 3 does not flow on the metal plate 4, so that characteristic deterioration of the antenna 3 can be avoided. Furthermore, since the electrical length of the metal plate 4 is close to a half wavelength at the resonance frequency of the antenna 3, that is, in the case of this embodiment, a double resonance is caused by both. As a result, it is possible to obtain broadband characteristics.

  In the above-described embodiment, the communication system is GPS, but other communication systems such as a cellular phone, Bluetooth, and LAN may be used. In addition, the metal plate 4 may be formed integrally with the housing, a metal film deposited or plated on the housing, or a conductive pattern formed on a flexible substrate or a printed circuit board. The antenna 3 may be configured as a pattern on the substrate, configured from a metal plate or metal foil, or formed by vapor deposition or plating on the casing.

  Next, a second embodiment of the present invention will be described. FIG. 2A is a side view with a cross section of a part of the mobile phone of the present embodiment, and FIG. 2B is a front view. 2a and 2b, elements similar to those of the first embodiment shown in FIGS. 1a and 1b are indicated by the same reference numerals. The mobile phone of the present embodiment includes an upper housing 1A and a lower housing 1B that are foldably connected via a hinge 1C.

  The upper housing 1A includes a receiver 5, a liquid crystal display panel 9, a liquid crystal holder 10 that reinforces the liquid crystal display panel 9, a circuit board 2, a high-frequency wireless circuit 8 mounted on the circuit board 2, and a circuit board. 2 and the metal plate 24 are provided. The liquid crystal holder 10 is made of a conductive metal such as a magnesium alloy so as to surround the periphery of the liquid crystal display panel 9 excluding the display surface. The liquid crystal holder 10 and the ground pattern of the circuit board 2 are conductively connected by metal springs 11 at a plurality of locations. The receiver 5 is disposed at the upper end of the upper housing 1A. The antenna 3 is a 1 / 4λ inverted L antenna system for receiving GPS (Global Positioning System), and is mounted on the upper end of the circuit board 2. The high frequency radio circuit 8 is a GPS receiving circuit, and is electrically connected to the antenna 3 through a transmission line. The lower housing 1B includes a transmitter 6 and operation keys 7, and has a circuit board (not shown) inside. The antenna 3 and the high-frequency radio circuit 8 in the present embodiment are for GPS as in the first embodiment.

  FIG. 2 c shows the metal plate 24 in detail. The metal plate 24 is formed by a pattern on the flexible substrate 26, and includes a first metal pattern 24A disposed in the center and a second metal pattern 24B disposed on both sides of the first metal pattern 24A. Is provided. On the flexible substrate 26, the switch element 12 that can switch the connection between the first metal pattern 24A and the second metal pattern 24B between conduction and non-conduction is further mounted. On the flexible substrate 26, the control line 13 for supplying a control signal from the circuit board 2 to the switch element 12 and the control line 13 are also connected to the antenna resonance from the first and second metal patterns 24A and 24B. A choke filter 14 for electrically opening in the frequency band is mounted. The control line 13 is connected to a connector 15 mounted on the circuit board 2. The second metal pattern 24B is provided with a slit 24E, which increases the electrical length of the second metal pattern. The electrical length of the first metal pattern 24 </ b> A is shorter than a half wavelength at the resonance frequency of the antenna 3. The electrical length when the first metal pattern 24 </ b> A and the second metal pattern 24 </ b> B are conductively connected by the switch element 12 is longer than a half wavelength at the resonance frequency of the antenna 3.

  According to the present embodiment, the same effects as those of the first embodiment can be obtained, and the size of the metal plate 24, that is, the resonance wavelength of the metal plate 24 can be switched according to the use state of the mobile phone. Thus, the metal plate 24 can be switched and operated as a reflector or a director for the antenna 3. In addition, since the slit 24E is provided in the second metal pattern 24B, the metal plate 24 should have an electric length sufficient to operate as a reflector in a limited space in the mobile phone terminal. It is possible.

  FIG. 2d is a diagram showing a call use state of the mobile phone terminal according to the present embodiment. In this figure, a state is shown in which a person holds the mobile phone terminal of the present embodiment so as to operate while looking at the liquid crystal display unit. For example, as shown in this figure, when the mobile phone terminal is held and a GPS signal is received from a GPS satellite, the switch element 12 is turned off, and the first metal pattern 24A and the second metal pattern 24B. Is electrically disconnected, the electrical length of the metal plate 24 is made shorter than a half wavelength at the resonance frequency of the antenna 3, and the metal plate 24 is operated as a waveguide so that the radiation pattern of the antenna 3 can be carried. It can be directed in the forward direction of the telephone terminal, that is, in the high elevation angle direction 21.

  However, if it is determined that the GPS satellite is not positioned in the high elevation angle direction 21 at a certain positioning timing and sufficient GPS signals cannot be received and the positioning accuracy does not increase, the switch element 12 is turned on. The first metal pattern 24A and the second metal pattern 24B are electrically connected, the electrical length of the metal plate 24 is made longer than a half wavelength at the resonance frequency of the antenna 3, and the metal plate 24 is made a reflector. As a result, the radiation pattern of the antenna 3 can be switched to the back direction of the mobile phone terminal, that is, the horizontal plane direction, and signals from GPS satellites located in the low elevation direction 22 can be received better. It becomes like this.

  In the present embodiment, the communication system is GPS, but other communication systems such as a cellular phone, Bluetooth, and LAN may be used. Further, the metal plate 24 is a sheet metal, metal foil, one integrally molded with the casing, a metal film deposited or plated on the casing, or a conductive pattern formed on the printed circuit board. It doesn't matter. Further, the second metal pattern 24B may be one on one side or three or more. In addition, the antenna 3 is configured as a pattern on a substrate, configured with a metal plate or metal foil, configured with a pattern on a flexible substrate, integrated with a housing, It may also be formed by vapor deposition or plating on the casing.

  Next, a third embodiment of the present invention will be described. FIG. 3A is a side view showing a cross-section of a part of a mobile phone terminal of the third embodiment of the present invention, and FIG. 3B is a front view.

  3a and 3b, elements similar to those of the mobile phone of the first embodiment shown in FIGS. 1a and 1b are indicated by the same reference numerals. The mobile phone of the present embodiment includes an upper housing 1A and a lower housing 1B that are foldably connected via a hinge 1C.

  The upper housing 1A includes a receiver 5, a liquid crystal display panel 9, a liquid crystal holder 10 that reinforces the liquid crystal display panel 9, a circuit board 2, a high-frequency wireless circuit 8 mounted on the circuit board 2, and a circuit board. 2 and the metal plate 34 are provided. The liquid crystal holder 10 is made of a conductive metal such as a magnesium alloy so as to surround the periphery of the liquid crystal display panel 9 excluding the display surface. The liquid crystal holder 10 and the ground pattern of the circuit board 2 are conductively connected by metal springs 11 at a plurality of locations. The receiver 5 is disposed at the upper end of the upper housing 1A. The antenna 3 is mounted on the upper end of the circuit board 2. The high frequency radio circuit 3 is electrically connected to the antenna 3 through a transmission line. The lower housing 1B includes a transmitter 6 and operation keys 7, and has a circuit board (not shown) inside.

  The antenna 3 and the high-frequency radio circuit 8 are for cellular phones corresponding to two frequency bands, that is, the f1 band and the f2 band, and the antenna 3 resonates in the f1 band and the f2 band. Here, the f1 band is a low frequency band and the f2 band is a high frequency band.

  FIG. 3 c shows the metal plate 34 in detail. The metal plate 34 is formed by a pattern on the flexible substrate 36, and includes a first metal pattern 34A disposed in the center and a second metal pattern 34B disposed on both sides of the first metal pattern 34A. Is provided. A filter element 16 that transmits the f1 band and blocks the f2 band is further mounted on the flexible substrate 36. The first metal pattern 34A and the second metal pattern 34B are connected via the filter element 16. The electrical length of the first metal pattern 34A is set to a half wavelength of approximately the f2 band. The electrical length when the first metal pattern 34A and the second metal pattern 34B are conductively connected at the position where the filter element 16 is mounted is set to a half wavelength of the f1 band.

  In the present embodiment, when the f1 band is used in the cellular telephone, the filter element 16 passes the f1 band, so that the first metal pattern 34A and the second metal pattern 34B are conductively connected. The electrical length of the metal plate 34 is approximately half the wavelength of the f1 band. At this time, the antenna 3 and the metal plate 34 have multiple resonances in a substantially f1 band, and a broadband antenna characteristic can be obtained.

  In addition, when the f2 band is used in the cellular phone, the filter element 16 does not transmit the f2 band, so that the first metal pattern 34A and the second metal pattern 34B are not conductively connected, and the electric power as the metal plate 34 is not connected. The length is approximately a half wavelength of the f2 band. At this time, the antenna 3 and the metal plate 34 cause double resonance in a substantially f2 band, and a broadband antenna characteristic is obtained.

  According to this embodiment, the same effect as that of the first embodiment can be obtained, and the same effect can be obtained for each frequency band in a system corresponding to a plurality of frequency bands.

In this embodiment, the communication system is a cellular phone, but other communication systems such as Bluetooth and LAN may be used. Further, the metal plate 34 is a sheet metal, metal foil, one integrally molded with the housing, a metal film deposited or plated on the housing, or a conductive pattern formed on the printed circuit board. It doesn't matter. Further, the second metal pattern 34B may be only one on each side, or may be three or more. In addition, the antenna 3 is configured as a pattern on a substrate, configured with a metal plate or metal foil, configured with a pattern on a flexible substrate, integrated with a housing, It may also be formed by vapor deposition or plating on the casing. The radio of the modification includes a circuit board on which a high-frequency radio circuit is mounted, an antenna connected to the high-frequency radio circuit, a metal plate that is not conductively connected to a ground pattern of the circuit board, the circuit board, and the antenna. The metal plate is arranged between the antenna and the receiver, and the metal plate and the ground pattern of the circuit board are arranged close to each other. As a result, when the head of the human body approaches the metal plate in a call-use state, the metal plate is capacitively coupled to the ground pattern of the circuit board via the human body head, and the metal plate becomes a ground plate to shield the antenna from the human head. However, while reducing the deterioration of the antenna characteristics due to the human body and the influence of the antenna radio wave on the human body, the metal plate floats electrically in a state where the human body is not in close proximity, and is in a non-powered and ungrounded state. Can be avoided. The radio device according to another modification further includes a conductive component that is conductively connected to the ground pattern of the circuit board, and the metal plate is not conductively connected to the conductive component and is disposed close to the conductive pattern. You may do it. As a result, when the head of the human body is close to the metal plate in a call use state, the metal plate is capacitively coupled to the conductive component through the head of the human body, and when the human body is not in proximity, the metal plate is electrically floating. It becomes a state of no power supply and no grounding. Therefore, even when the antenna or the metal plate is disposed at a position away from the circuit board, the same effect as described above can be obtained. In still another modification, the metal plate may be composed of a plurality of metal plate pieces, and each metal plate piece may be connected by an element that can be switched between conduction and insulation. As a result, in a state where the human head is not in proximity, the operation of the metal plate as a reflector or director is switched by switching the connection state of the metal plate pieces according to the usage scene, and the radiation direction of the antenna radio wave is changed. It is possible to switch. In still another modification, the metal plate may be composed of a plurality of metal plate pieces, and each metal plate piece may be connected by a frequency selection element. As a result, in a state where the human head is not in proximity, the connection state between the metal plate pieces is changed by the frequency selection element according to each frequency band even for a system in which the antenna supports multiple frequencies. Since the electrical length changes, the metal plate can have a desired resonance wavelength.

  The present invention is applicable to mobile communication devices such as mobile phones.

It is a side view of the mobile telephone terminal of the 1st Embodiment of this invention. It is a top view of the mobile telephone terminal of the 1st Embodiment of this invention. It is a figure which shows the telephone call use state of the mobile telephone terminal of the 1st Embodiment of this invention. It is a side view of the mobile telephone terminal of the 2nd Embodiment of this invention. It is a top view of the mobile telephone terminal of the 2nd Embodiment of this invention. It is a figure which shows the metal plate of the mobile telephone terminal of the 2nd Embodiment of this invention in detail. It is a figure which shows the telephone call use state of the mobile telephone terminal of the 2nd Embodiment of this invention. It is a side view of the mobile telephone terminal of the 3rd Embodiment of this invention. It is a top view of the mobile telephone terminal of the 3rd Embodiment of this invention. It is a figure which shows the metal plate of the mobile telephone terminal of the 3rd Embodiment of this invention in detail. It is a side view of the conventional mobile telephone terminal. It is a figure which shows the telephone call use state of the conventional mobile telephone terminal. It is a perspective view explaining a ground pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A Upper housing | casing 1B Lower housing | casing 1C Hinge 2 Circuit board 3 Antenna 4, 24, 34 Metal plate 5 Reception part 6 Transmission part 7 Operation key 8 High frequency radio circuit 9 Liquid crystal display panel 10 Liquid crystal holder 11 Metal spring 12 Switch element 13 Control line 14 Choke filter 15 Connector 16 Filter 26, 36 Flexible substrate 24A, 34A First metal pattern 24B, 34B Second metal pattern 24E Slit

Claims (9)

A circuit board;
An antenna connected to a radio circuit;
A metal plate not conductively connected to the ground pattern of the circuit board;
And a conductive connection electrically conductive component and the ground pattern,
The metal plate is disposed between the antenna and the receiver;
The wireless device, wherein the metal plate and the conductive component are capacitively coupled when a human head is close to the receiver . A housing for housing the circuit board;
2. The wireless device according to claim 1, wherein a gap between the metal plate and the conductive component is close to a surface of the housing on the side of the receiving unit. A housing for accommodating the prior SL circuit board,
A display panel ,
The display panel and the receiver are arranged on one surface of the housing,
2. The wireless device according to claim 1, wherein the metal plate and the conductive component are arranged in a plane substantially in the same plane as the display surface of the display panel through a gap. Radio machine according to any one of claims 1 to 3, wherein the resonant wavelength of the metal plate is substantially identical to the resonance wavelength of the antenna. The wireless device according to any one of claims 1 to 3, wherein a resonance wavelength of the metal plate is longer than a resonance wavelength of the antenna. The wireless device according to any one of claims 1 to 3, wherein a resonance wavelength of the metal plate is shorter than a resonance wavelength of the antenna. Radio according to any one of claims 1 to 6, characterized in that the slits on the metal plate. The metal plate has a first metal piece and a second metal piece,
By switching the conduction state between the first metal piece and the second metal piece, it is possible to switch whether the electrical length of the metal plate is longer or shorter than a half wavelength at the resonance frequency of the antenna. The wireless device according to any one of claims 1 to 7 , characterized in that: The metal plate has a first metal piece and a second metal piece,
The first metal piece and the second metal piece are connected via a filter element,
The wireless device according to any one of claims 1 to 7 , wherein the filter element transmits a part of a frequency used by the wireless device and blocks the other part.

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