JP2007207857A - Portable terminal and printed board therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board for portable terminal in which electronic components can be protected against malfunction or breakdown even if static electricity is applied directly from the seam of a containing case, and to provide a portable terminal employing it. <P>SOLUTION: In the printed wiring board for portable terminal contained in a case 8 made by combining two or more cover members, static electricity GND wiring 7 is provided in proximity to the seam of the case separately from GND wiring 6 for operating an electronic component being mounted, and the static electricity GND wiring 7 is connected with the minus pole of a BATT 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printed circuit board for a portable terminal applied to the portable terminal and a portable terminal using the same.

  A printed wiring board (hereinafter referred to as PWB) applied to a portable terminal needs to take measures when static electricity charged by a user is discharged from the hand.

6 and 7 show the configuration of the main part of a conventional portable terminal.
The PWB 21 is a printed wiring board. The signal line 22 is an electric wiring (wiring pattern) formed on the PWB 21 and electrically connects the ICs 23 to each other. The ICs 23 are control devices related to the operation of the mobile terminal. The Zener diode 24 is connected to the signal line 22 in parallel, and is an electrostatic protection diode that releases current to the GND wiring 26 when an excessive voltage is applied to the signal line 22 (electrostatic discharge or the like). The BATT 25 is a power source for operating the mobile terminal, and has positive and negative electrodes. The GND wiring 26 is connected to the negative pole of the BATT 25. The housing 28 is an outer mold cover of the mobile terminal body. The fitting portion 29 is a portion that becomes a joint of the housing 28.

  As shown in the drawing, a predetermined amount of clearance (a space between the housing 28 and the PWB 21) is provided in the vicinity of the fitting portion 29.

A mechanism by which malfunction occurs due to electrostatic discharge in a conventional portable terminal will be described.
The static electricity acts on the PWB 21 via the fitting portion 29 of the housing 28, and the discharge voltage is applied to the signal line 22 which is a conductor wiring. The Zener diode 24 prevents the ICs 23 from being overdamaged by the electrostatic discharge voltage by causing a current due to the electrostatic discharge applied to the signal line 22 to flow to the GND wiring 26, thereby preventing destruction. The static electricity flows into the GND wiring 26 and flows into the BATT 25, thereby preventing the ICs 23 from being destroyed or malfunctioning.

  However, in actual mobile terminals, the number of signal lines reaches several hundreds, so it is practically impossible to install Zener diodes in all of them due to restrictions on the mounting area.

  In addition, by securing a large clearance, static electricity can be hardly applied to the PWB 21 from the outside of the housing. However, if the clearance is large, an increase in the size of the mobile terminal is unavoidable. Can't answer your needs.

As a related art regarding countermeasures against static electricity in a portable terminal, there is an “electronic circuit board” disclosed in Patent Document 1. The invention disclosed in Patent Document 1 is grounded via a ground pattern for electrostatic discharge in order to “ground” static charges that have entered the housing from an electronic component.
JP-A-5-102624

  However, the invention disclosed in Patent Document 1 is effective against static electricity from electronic components, but protects the electronic components against static electricity directly applied to the PWB in the housing from the joints of the housing. I can't.

  The present invention has been made in view of such a problem, and a printed wiring board for a portable terminal capable of protecting an electronic component from malfunctioning and destruction even when static electricity is directly applied from a joint of housings to be accommodated, and a mobile phone using the same The purpose is to provide a terminal.

In order to achieve the above object, the present invention provides, as a first aspect, a printed wiring board for a portable terminal housed in a casing of a portable terminal formed by combining two or more cover members,
Separately from the first ground wiring for operating the mounted electronic component, a second ground wiring is provided in the vicinity of the joint portion between the cover members, and the second ground wiring is a negative electrode of the storage battery. The present invention provides a printed wiring board for a portable terminal, characterized in that the printed circuit board is connected to the mobile terminal.

  In the first aspect of the present invention, it is preferable that the second ground wiring is disposed at the peripheral portion.

  In any of the above configurations of the first aspect of the present invention, it is preferable that the first ground wiring and the second ground wiring are electrically connected in at least one place. In addition, it is preferable to include a third ground wiring for connecting the connector part exposed outside the housing and the negative electrode of the storage battery. In addition to this, two or more connector parts are mounted, and the third ground wiring is connected to each connector. It is more preferable to connect the component and the negative electrode of the storage battery.

  In the configuration including the third ground wiring of the first aspect of the present invention, it is more preferable that the third ground wiring is electrically connected to at least one of the first and second ground wirings.

  In any of the above configurations of the first aspect of the present invention, it is preferable that the second ground wiring is provided on both the front and back surfaces.

  Moreover, in order to achieve the said objective, this invention provides the portable terminal using the printed wiring board for portable terminals concerning the structure in any one of the said 1st aspect of the said invention as a 2nd aspect. is there.

  ADVANTAGE OF THE INVENTION According to this invention, even if static electricity is directly applied from the joint of the housing | casing to accommodate, the printed wiring board for portable terminals which can protect an electronic component from a malfunction or destruction, and a portable terminal using the same can be provided.

[First Embodiment]
A first embodiment in which the present invention is suitably implemented will be described. FIG. 1 shows a configuration of a main part of a mobile terminal according to the present embodiment. PWB 1 is a printed wiring board accommodated in the housing 8. The signal line 2 is an electrical wiring (wiring pattern) in the PWB 1 and electrically connects the ICs 3 to each other. The ICs 3 are control devices related to the operation of the mobile terminal. BATT 5 is a power source for operating the mobile terminal, and includes a plus electrode and a minus electrode. The GND wiring 6 is electrically connected to the negative electrode of the BATT 5. The static electricity GND 7 is disposed at the peripheral edge (in other words, at the outermost periphery) surrounding the PWB 1, and is connected to the negative electrode of the BATT 5 separately from the GND wiring 6. When PWB 1 is a multilayer substrate, static electricity GND 7 is provided on the outer periphery of all layers. The housing 8 is an outer mold cover of the mobile terminal body. The fitting portion 9 is a joint portion of the housing 8.
It is preferable that the static electricity GND 7 and the negative electrode of BATT 5 are connected with a shortest distance using a sufficiently thick wiring. If the wiring connecting the static electricity GND 7 and the negative pole of BATT 5 is too thin, the static electricity will not flow smoothly into the negative pole of BATT 5, so the effect of protecting the ICs 3 will be reduced. Further, when the static electricity GND 7 and the negative pole of BATT 5 are not connected at the shortest distance, the probability of overlapping with other signal lines or running side by side increases, so the effect of protecting the ICs 3 is reduced.

  As shown in the figure, the fitting portion 9 is provided with a predetermined clearance (the interval from the housing 8 to the PWB 1).

FIG. 2 shows a mechanism of electrostatic discharge in the portable terminal according to the present embodiment.
When static electricity is applied to the PWB 1 from the fitting portion 9 of the housing 8, the static electricity GND 7 is disposed on the outermost periphery of the PWB 1, so that a discharge occurs in the static electricity GND 7 instead of the signal line 2. That is, the static electricity GND 7 serves as a lightning rod. The charge due to the static electricity discharged by the static electricity GND 7 flows into the negative electrode of BATT 5. As described above, even when static electricity is applied to the PWB 1 from the fitting portion 9, no charge due to static electricity flows through the signal line 2, thereby preventing destruction and malfunction of the ICs 3.

  Even if static electricity is applied to the PWB 1, the current due to the discharge flows into the static electricity GND 7 instead of the signal line 2, so that the clearance between the housing 8 and the PWB 1 can be reduced. That is, it is suitable for reducing the size of the portable terminal.

  As described above, since the mobile terminal according to the present embodiment takes countermeasures against static electricity without using a Zener diode, the mounting area of the PWB can be reduced and the cost can be reduced. Furthermore, since the clearance between the housing and the PWB can be reduced, it is effective for reducing the size and thickness of the portable terminal.

  Here, the configuration in which the outer periphery of the PWB 1 is closest to the joint of the housing 8 is taken as an example. However, the portion other than the peripheral portion of the PWB 1 is closest to the joint of the housing 8 as shown in FIG. However, the same effect can be obtained. When a specific part of the surface of the PWB 1 is closest to the joint of the housing 8, the static electricity GND 7 may be provided only on the uppermost layer for that part.

[Second Embodiment]
A second embodiment in which the present invention is suitably implemented will be described.
FIG. 4 shows a configuration of a main part of the mobile terminal according to the present embodiment. The portable terminal according to this embodiment is the same as that of the first embodiment except that the portable terminal further includes an external connector 31.

The external connector 31 is the same as that provided in a conventional portable terminal (for example, a charging connector or a headphone jack), and a plug-like one is inserted from the outside by at least the user's manual work. .
Here, a configuration in which two external connectors 31 are provided is taken as an example, but the number of external connectors 31 may be one or three or more.

  The external connector GND 32 is electrically connected to the external connector 31, and is connected to the negative pole of BATT 5 separately from the GND wiring 6.

  Since the external connector 31 is the part that is most easily touched by the user, the external connector 31 is the part that has the highest probability of electrostatic discharge.

FIG. 5 shows a mechanism of electrostatic discharge in the portable terminal according to the present embodiment.
When the user tries to insert the external connector 31 such as a headphone jack, static electricity charged to the user is discharged to the external connector 31. The static charge flows into the negative pole of BATT 5 via the external connector GND 32 without flowing into the signal line 2. Since current due to electrostatic discharge does not flow through the signal line 2, it is possible to prevent the IC 3 from being broken or malfunctioning.

Each of the above embodiments is an example of a preferred embodiment of the present invention, and the present invention is not limited to these.
For example, in the above embodiments, the static electricity GND 7 and the external connector GND 32 are grounded independently of the GND wiring 6, but the static electricity GND 7 and the external connector GND 32 are electrically connected to the GND wiring 6 in some places. It may be connected.
As described above, the present invention can be variously modified.

It is a principal part perspective view of the portable terminal concerning 1st Embodiment which implemented this invention suitably. It is principal part sectional drawing of the portable terminal concerning 1st Embodiment. It is a side view which shows an example of the structure where parts other than the peripheral part of PWB are closest to the joint of a housing | casing. It is a principal part perspective view of the portable terminal concerning 2nd Embodiment which implemented this invention suitably. It is principal part sectional drawing of the portable terminal concerning 2nd Embodiment. It is a principal part perspective view of the conventional portable terminal. It is principal part sectional drawing of the conventional portable terminal.

Explanation of symbols

1 PWB
2 Signal line 3 IC 5 BATT (battery)
6 GND wiring 7 Electrostatic GND wiring 8 Case 9 Mating part 31 External connector 32 External connector GND wiring

Claims (8)

A printed wiring board for a portable terminal housed in a casing of a portable terminal formed by combining two or more cover members,
Separately from the first ground wiring for operating the mounted electronic component, a second ground wiring is provided in the vicinity of the joint portion between the cover members, and the second ground wiring is connected to the storage battery. A printed wiring board for a portable terminal, characterized by being connected to a negative electrode.   2. The printed wiring board for a portable terminal according to claim 1, wherein the second ground wiring is disposed at a peripheral portion.   The printed wiring board for a portable terminal according to claim 1 or 2, wherein the first ground wiring and the second ground wiring are electrically connected at least at one place.   The printed wiring board for a portable terminal according to any one of claims 1 to 3, further comprising a third ground wiring that connects a connector component exposed outside the casing and a negative electrode of the storage battery.   5. The printed wiring board for a portable terminal according to claim 4, wherein two or more of the connector parts are mounted, and the third ground wiring connects each of the connector parts and a negative electrode of the storage battery.   6. The printed wiring board for a portable terminal according to claim 4, wherein the third ground wiring is electrically connected to at least one of the first and second ground wirings.   The printed wiring board for a portable terminal according to any one of claims 1 to 6, wherein the second ground wiring is provided on both the front and back surfaces.   The portable terminal using the printed wiring board for portable terminals of any one of Claim 1 to 7.

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