JP2009278206A - Mobile terminal unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal unit capable of reducing the influence of noise on radio signals received by an antenna. <P>SOLUTION: The mobile terminal unit 10 includes: a first circuit board 21 having a ground pattern 11A configuring the antenna; a second circuit board 22 loaded with a radio circuit 12 for processing the radio signals from the antenna; first signal wiring 23 for connecting the ground pattern 11A of the first circuit board 21 and the radio circuit 12; second signal wiring 24 for connecting the first circuit board 21 and the second circuit board 22, disposed away from the first signal wiring 23; and a grounding line 25 for connecting the ground pattern 11A of the first circuit board 21 and the ground pattern 11B of the second circuit board 22 and extending adjacent to the second signal wiring 24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a portable terminal device, and more specifically, a circuit board connected to an antenna or a circuit board having a ground pattern constituting the antenna, and a circuit board on which a radio circuit for processing a radio signal from the antenna is mounted. The present invention relates to a portable terminal device.

  Among portable terminal devices such as mobile phones, one that exchanges various signals between a circuit board arranged in an upper housing and a circuit board arranged in a lower housing via a flexible substrate or a cable is known. (For example, Patent Documents 1 and 2).

  Japanese Patent Application Laid-Open No. 2004-228688 discloses an upper case in which a circuit board to which an antenna is connected is arranged, a lower case in which a circuit board to which a radio circuit is connected is arranged, a coaxial line that connects the antenna and the radio circuit, and a flexible circuit A portable radio with a substrate is described. In this portable wireless device, the antenna is not disposed on the ground region of the circuit board of the upper housing, thereby reducing the influence of the ground region on the antenna.

  Patent Document 2 includes an upper casing in which circuit boards are arranged, a lower casing in which circuit boards to which antennas are connected are arranged, and a cable that connects circuit boards to each other via connectors of the circuit boards. A portable radio is described. In this portable wireless device, the ground line of the cable is connected to the ground pattern lead portion of each circuit board. Each core wire of the cable and the wiring in each circuit board are electrically connected via a connector.

  In the portable wireless device described in Patent Document 2, the ground current caused by the antenna current is directed from the ground pattern of the circuit board of the upper housing to the ground pattern of the circuit board of the lower housing via the ground wire of the cable. Flowing. Therefore, the antenna current easily flows from the circuit board of the lower casing toward the circuit board of the upper casing without depending on the connection position of the connector.

JP 2007-158915 A JP 2006-005567 A

  In Patent Document 1, when a radio signal received by an antenna is transmitted to a radio circuit, the radio signal is affected by noise (self-generated noise) generated on a circuit board or a flexible board of the lower housing. Is not considered.

  Patent Document 2 is a technology that makes it easy to flow an antenna current by flowing a ground current caused by an antenna current from a circuit board of an upper housing toward a circuit board of a lower housing using a ground wire of a cable. is there. However, it is insufficient in terms of noise countermeasures for radio signals.

  An object of this invention is to provide the portable terminal device which can reduce the influence of the noise with respect to the radio signal received with the antenna.

In order to achieve the above object, the present invention includes a first circuit board connected to an antenna,
A second circuit board on which a radio circuit for processing radio signals from the antenna is mounted;
The first circuit board and the second circuit board are connected to each other, the first signal wiring for transmitting a radio signal from the antenna to the wireless circuit, and the first signal wiring spaced apart from the first signal wiring. A second signal wiring provided;
Provided is a portable terminal device comprising a ground line connecting the ground pattern of the first circuit board and the ground pattern of the second circuit board and extending adjacent to the second signal wiring. To do.

The present invention also includes a first circuit board having a ground pattern constituting an antenna,
A second circuit board on which a radio circuit for processing radio signals from the antenna is mounted;
A first signal wiring for connecting the ground pattern of the first circuit board and the wireless circuit; and a connection between the first circuit board and the second circuit board; A second signal wiring that is spaced apart;
Provided is a portable terminal device comprising a ground line connecting the ground pattern of the first circuit board and the ground pattern of the second circuit board and extending adjacent to the second signal wiring. To do.

  According to the mobile terminal device of the present invention, the influence of noise on the radio signal received by the antenna can be reduced by arranging the ground line extending adjacent to the second signal wiring.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of a mobile terminal device according to an embodiment of the present invention. The mobile terminal device 10 is a mobile phone, for example, and has various functions including a communication function that enables telephone calls, mail transmission / reception, and Internet connection, a display function that displays various image data, and the like. In the figure, among various functions, communication functions are shown. The mobile terminal device 10 includes a receiver-side substrate (first circuit board) 21 disposed in the upper housing 20A and a microphone-side substrate (second circuit substrate) 22 disposed in the lower housing 20B. Yes. The mobile terminal device 10 is a foldable type in which an upper housing 20A and a lower housing 20B are rotatably coupled by a hinge (not shown).

  The mobile terminal device 10 employs a so-called housing dipole antenna. The case dipole antenna uses the case as an antenna element. The antenna here includes a ground pattern 11A on the receiver-side substrate 21, a ground pattern 11B on the microphone-side substrate 22, and an antenna feed line (first signal wiring) 23 that connects the ground patterns 11A and 11B. That is, the ground patterns 11A and 11B arranged substantially symmetrical to each other function as antenna elements (conductive wires).

  The wireless unit 12 is disposed on the microphone side substrate 22. The radio unit 12 performs a process of demodulating a radio signal (antenna current) received by the antenna into an audio signal or the like. The microphone-side substrate 22 is mounted with various digital circuits for controlling various functions of the mobile terminal device 10.

  The receiver side substrate 21 and the microphone side substrate 22 are electrically connected by the antenna feeding line 23, the signal transmission substrate (second signal wiring) 24, and the noise countermeasure substrate (ground line) 25. The antenna current distributed and flowing in the ground pattern 11 </ b> A of the receiver-side substrate 21 flows through the antenna feeding line 23. The antenna power supply line 23 has one end connected to the ground pattern 11A and the other end connected to the ground pattern 11B. An antenna feeding port 23a constituting the other end of the antenna feeding line 23 is connected to the wireless unit 12 via a signal line 23b. With this configuration, the antenna current is transmitted to the radio unit 12 via the ground pattern 11A of the receiver-side substrate 21, the antenna feed line 23, and the signal line 23b.

  The signal transmission board 24 is a flexible board, and is arranged away from the antenna power supply line 23. The signal transmission board 24 is a line for transmitting various digital signals different from the antenna current, and has one end connected to the receiver side board 21 and the other end connected to the microphone side board 22. Examples of the various signals include a control signal for controlling a liquid crystal display (LCD) that is arranged on the surface of the upper housing 20A and displays various image data. That is, a control signal is transmitted from the microphone side substrate 22 to the receiver side substrate 21 via the signal transmission substrate 24. The signal transmission board 24 includes a pair of power supply lines, and the inner ground lines of the pair of power supply lines are electrically connected to the ground patterns 11A and 11B.

  The noise countermeasure board 25 is a metal flexible belt-like board, and is located on the side opposite to the signal transmission board 24 when viewed from the antenna feeding line 23 and extends adjacent to the signal transmission board 24. Yes. The noise countermeasure substrate 25 has one end connected to the ground pattern 11A and the other end connected to the ground pattern 11B.

  FIG. 2 is a diagram illustrating a side surface of the circuit board in the mobile terminal device 10 of FIG. The signal transmission board 24 is mounted on both board surfaces 21 a and 22 a of the receiver side board 21 and the microphone side board 22. Further, the noise countermeasure substrate 25 is mounted on the substrate rear surfaces 21 b and 22 b of both the receiver side substrate 21 and the microphone side substrate 22. In the figure, an example in which the ground patterns 11A and 11B are formed in layers inside the receiver side substrate 21 and the microphone side substrate 22 is shown. In this case, the ground patterns 11A and 11B and the noise countermeasure board 25 are connected via a conductor plug or the like. The ground patterns 11A and 11B may be formed on the front surfaces 21a and 22a and the back surfaces 21b and 22b of the receiver side substrate 21 and the microphone side substrate 22.

  With reference to FIG.3 and FIG.4, operation | movement of the portable terminal device 10 which concerns on this embodiment is demonstrated. 3 and 4, the circuit configuration 10A of the mobile terminal device 10 is shown for convenience. 3 and 4, the control unit 13 that controls the wireless unit 12 is shown as an example among various digital circuits mounted on the microphone-side substrate 22.

  FIG. 3 is a diagram showing the distribution of antenna current and noise current in the mobile terminal device 10. Reference numeral 31 shown in FIG. 3 indicates an antenna current path that is particularly susceptible to noise from the signal transmission board 24. The antenna current 31 flows in the vicinity of the edge of the receiver-side substrate 21, which is a position close to the signal transmission substrate 24.

  An antenna current 32 obtained by joining the antenna current 31 and the antenna current flowing in another path formed in the ground pattern 11 </ b> A of the receiver side substrate 21 flows through the antenna feeding line 23. The antenna current 32 is transmitted to the wireless unit 12 via the power supply port 23a and the signal line 23b.

  On the other hand, in the microphone-side substrate 22, the control unit 13 or the like constituting the digital circuit serves as a noise generation source and generates a noise current. Here, a case where the noise countermeasure board 25 is not installed will be described. In this case, all noise currents caused by noise components generated from the control unit 13 and the like flow through only the signal transmission board 24 and are transmitted to the receiver side board 21. The transmitted noise current interferes with the antenna current, and particularly strongly interferes with the antenna current 31. For this reason, the antenna current 32 is affected by the noise current. It is conceivable that the noise current directly interferes with the antenna current 32. Thus, the radio signal (radio component) received by the antenna interferes with the noise current flowing through the signal transmission board 24, and the antenna reception sensitivity of the mobile terminal device 10 deteriorates.

  On the other hand, in the mobile terminal device 10 of the present embodiment, since the noise countermeasure board 25 is installed, the noise current includes the noise current 33 flowing in the signal transmission board 24 and the noise flowing in the noise countermeasure board 25. Dispersed in the current 34, and flows particularly in the noise countermeasure board 25. Since the noise countermeasure board 25 is disposed on the side opposite to the signal transmission board 24 and adjacent to the signal transmission board 24 when viewed from the antenna power supply line 23, the noise current 34 includes the antenna current 31, 32 is difficult to interfere with.

  Further, since the noise countermeasure substrate 25 is formed in a belt-like pattern, the coupling capacitance with the signal transmission substrate 24 is large, and the noise current 34 easily flows. Thus, by arranging the noise countermeasure board 25, the noise current 33 that may interfere with the antenna currents 31 and 32 is reduced. By reducing the noise current 33, the amount of noise that interferes with the antenna currents 31 and 32 is reduced, and deterioration of the antenna reception sensitivity of the mobile terminal device 10 can be suppressed.

  FIG. 4 is a diagram illustrating a ground (GND) current in the mobile terminal device 10. First, the effect of noise generated on the receiver-side substrate 21 when the noise countermeasure substrate 25 is not installed will be described. Between the receiver side substrate 21 and the microphone side substrate 22, only the signal transmission substrate 24 having a ground line having a relatively large resistance component is disposed. For this reason, when a noise current flows from the ground pattern 11 </ b> A of the receiver side substrate 21 to the ground pattern 11 </ b> B of the microphone side substrate 22, a difference occurs between the ground potential of the microphone side substrate 22 and the ground potential of the receiver side substrate 21. That is, the ground potential of the ground pattern 11A rises due to noise generated in the receiver-side substrate 21. Thus, since the noise generated in the receiver-side substrate 21 affects the ground potential of the ground pattern 11A constituting the antenna, there is a concern that the characteristics of the antenna (characteristics of the single antenna) may deteriorate.

  On the other hand, in the mobile terminal device 10 of the present embodiment, the signal transmission substrate 24 and the noise countermeasure substrate 25 are arranged between the receiver side substrate 21 and the microphone side substrate 22. The inner ground line of the power supply line of the signal transmission board 24 is electrically connected to the ground patterns 11A and 11B. Further, the noise countermeasure substrate 25 directly connects the ground pattern 11A and the ground pattern 11B.

  With the above configuration, the ground current 41 flows through the signal transmission board 24, and the ground current 42 flows through the noise countermeasure board 25. When ground currents 41 and 42 flow through the signal transmission board 24 and the noise countermeasure board 25 arranged in parallel, the ground potential difference between the receiver side board 21 and the microphone side board 22 decreases. Due to the decrease in the ground potential difference, noise that occurs on the receiver-side substrate 21 and affects the characteristics of the antenna itself is reduced.

  According to this embodiment, the interference between the noise current and the antenna current is avoided, the deterioration of the radio signal that is the received wave is reduced, and communication is possible even with a lower electric field. That is, the antenna reception sensitivity of the mobile terminal device 10 can be improved. In addition, the ground potential difference between the receiver-side substrate 21 and the microphone-side substrate 22 can be reduced, noise generated in the receiver-side substrate 21 can be reduced, and the antenna characteristics of the mobile terminal device 10 can be improved.

  In the mobile terminal device of the above embodiment, even if noise is generated in the second circuit board, the noise current is separated from the first signal wiring, and the ground adjacent to the second signal wiring. It flows in a distributed manner with the line. Therefore, the radio signal transmitted through the first signal wiring is not easily affected by noise. Therefore, the antenna reception sensitivity can be improved. In addition, since the second signal wiring and the ground line are adjacent to each other, a ground current from the first circuit board to the second circuit board flows through the second signal wiring and the ground line. That is, the ground potential difference between the first circuit board and the second circuit board is reduced, and the generation of noise on the first circuit board can be reduced. Therefore, antenna characteristics can be improved.

  In the above embodiment, the casing dipole antenna is used for the mobile terminal device 10, but the present invention is not limited to this. As an example, a monopole type or rod type antenna 11 is disposed adjacent to the receiver side substrate 21 as in the circuit configuration 10B shown in FIG. The antenna 11 is connected to the wireless unit 12 via the receiver-side substrate 21 and the antenna feeding line 23 and the signal line 23b. The signal transmission board 24 and the noise countermeasure board 25 have the same configurations as those shown in FIGS.

  The antenna 11 may be a chip type antenna that is directly mounted on the receiver side substrate 21. Further, a sheet metal antenna may be formed by feeding power from the receiver side substrate 21 to the sheet metal or the like, or a rod type antenna may be used.

  In the above embodiment, the noise countermeasure board 25 is directly connected to the ground patterns 11A and 11B of the receiver side board 21 and the microphone side board 22, but the present invention is not limited to this. That is, the noise countermeasure board 25 may be connected to the ground patterns 11A and 11B via a connector, or may be connected via a through hole or the like. Further, the noise countermeasure substrate 25 may be connected to the ground patterns 11A and 11B via a conductive material, or may be connected to a sheet metal via a conductive material.

  In the mobile terminal device of the above embodiment, the ground line is formed as a strip pattern. By reducing the resistance component of the ground line, a noise current can easily flow.

  In addition, each of the ground line and the second signal wiring is formed of a flexible substrate. Accordingly, the first circuit board and the second circuit board can be applied to a foldable portable terminal device that is disposed in separate housings.

  The ground line is mounted on one surface of both the first and second circuit boards, and the second signal wiring is mounted on the other surface of both the first and second circuit boards. As a result, the ground line and the second signal line are brought closer to each other, and a noise current can easily flow through the ground line and the second signal line.

  The ground line is a metal plate and is in direct contact with the ground pattern of the first circuit board and the second circuit board. As a result, since the ground current from the first circuit board to the second circuit board flows through the ground line, the ground potential difference between the first circuit board and the second circuit board is reduced.

  The ground line and the second signal wiring are connected to the ground pattern of the first circuit board and the second circuit board via a connector. In this case, since the ground current flows through the ground line and the second signal wiring, the ground potential difference between the first circuit board and the second circuit board becomes smaller. Therefore, it is possible to reduce the generation of noise on the first circuit board.

  Further, the antenna may be a case dipole antenna having the ground patterns of the first circuit board and the second circuit board as elements.

  As mentioned above, although this invention was demonstrated based on the suitable embodiment, the portable terminal device of this invention is not limited only to the structure of the said embodiment, A various correction and change from the structure of the said embodiment. Those subjected to are also included in the scope of the present invention.

The figure which shows the structure of the portable terminal device which concerns on one Embodiment of this invention. The figure which shows the side surface of the circuit board in the portable terminal device shown in FIG. The figure which shows antenna current distribution and noise current distribution in the portable terminal device shown in FIG. The figure which shows the ground current in the portable terminal device shown in FIG. The figure which shows the circuit structure of the portable terminal device which has arrange | positioned the antenna of another system.

Explanation of symbols

10: Mobile terminal device 11: Antennas 11A, 11B: Ground pattern 12: Radio unit 13: Control unit 20A: Upper housing 20B: Lower housing 21: Receiver side substrate (first circuit substrate)
22: Microphone side substrate (second circuit board)
23: Antenna feed line (first signal wiring)
23a: feeding port 23b: signal line 24: signal transmission board (second signal wiring)
25: Noise suppression board (grounding line)
31, 32: Antenna current 33, 34: Noise current 41, 42: Ground current

Claims (8)

A first circuit board connected to the antenna;
A second circuit board on which a radio circuit for processing radio signals from the antenna is mounted;
The first circuit board and the second circuit board are connected to each other, the first signal wiring for transmitting a radio signal from the antenna to the wireless circuit, and the first signal wiring spaced apart from the first signal wiring. A second signal wiring provided;
A portable terminal device comprising a ground line connecting the ground pattern of the first circuit board and the ground pattern of the second circuit board and extending adjacent to the second signal wiring.   The portable terminal device according to claim 1, wherein the ground line is formed as a strip pattern.   The portable terminal device according to claim 1, wherein each of the ground line and the second signal wiring is formed of a flexible substrate.   The ground line is mounted on one surface of both the first and second circuit boards, and the second signal wiring is mounted on the other surface of both the first and second circuit boards. The portable terminal device as described in any one of Claims 1-3.   The portable terminal device according to claim 1, wherein the ground line is a metal plate and is in direct contact with a ground pattern of the first circuit board and the second circuit board.   5. The mobile phone according to claim 1, wherein the ground line and the second signal wiring are connected to a ground pattern of the first circuit board and the second circuit board via a connector. Terminal device. A first circuit board having a ground pattern constituting an antenna;
A second circuit board on which a radio circuit for processing radio signals from the antenna is mounted;
A first signal wiring for connecting the ground pattern of the first circuit board and the wireless circuit; and a connection between the first circuit board and the second circuit board; A second signal wiring that is spaced apart;
A portable terminal device comprising a ground line connecting the ground pattern of the first circuit board and the ground pattern of the second circuit board and extending adjacent to the second signal wiring.   The portable terminal device according to claim 7, wherein the antenna is a case dipole antenna having a ground pattern of the first circuit board and the second circuit board as an element.

Images