JP4077230B2 - Mobile communication terminal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile communication terminal such as a mobile phone or PDA (Personal Digital Assistants).
[0002]
[Prior art]
For mobile communication terminals represented by mobile phones, downsizing and weight reduction are one of the important issues. In particular, a so-called foldable mobile communication terminal in which the first casing and the second casing are connected to each other using a hinge mechanism so as to be opened and closed has a large dimension in the thickness direction of the terminal when folded. There is a demand for thinning of the first and second housings.
[0003]
On the other hand, in recent mobile communication terminals, in addition to the main display installed on the front surface of the housing, a sub-display is installed on the back surface of the housing. If a sub display is installed in addition to the main display, the user can check display information regardless of the orientation of the mobile communication terminal. In particular, in the case of a foldable mobile communication terminal, it is not necessary to open the casing each time in order to check the time, the operating state of the terminal, etc., and the convenience for the user is improved.
[0004]
[Problems to be solved by the invention]
However, the main display and the sub display are generally provided back-to-back in the same housing. For this reason, the thickness of the casing is further increased, portability is impaired, and design freedom is reduced.
[0005]
On the other hand, in order to reduce the thickness of the housing, it is also considered that circuit components such as integrated circuits are mounted in a concentrated position on a printed wiring board. However, when circuit components are concentratedly mounted at a specific position, the mounting density of the circuit components is increased, and electromagnetic or thermal interference is likely to occur between the circuit components. As a result, communication quality is deteriorated.
[0006]
The present invention has been made paying attention to the above circumstances, and the object of the present invention is to reduce the interference between circuit components while maintaining a good communication quality while reducing the thickness of the housing. Is to provide a mobile communication terminal.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a mobile communication terminal in which a printed wiring board on which circuit components are mounted and a display unit are accommodated in a housing, and the above-mentioned printed wiring board is forming a ground pattern forming a planar to a position facing the display unit, electromagnetic or thermally to each other to the first and second portions spaced above the ground pattern on one surface of the printed wiring board A function of separately mounting the first and second circuit components that require isolation and shielding at least one of the first and second circuit components between the printed wiring board and the display unit; that a shield case having both a function of holding the display unit, and configured to be installed in a state of being in electrical contact with the ground pattern A.
[0008]
Therefore, according to the present invention, the ground pattern is formed on the portion of the printed wiring board facing the display unit, and the circuit components are distributed and mounted on the periphery thereof. For this reason, compared with the case where circuit components are mounted on the entire surface of the printed wiring board, the distance between the printed wiring board and the display unit can be made closer, and the thickness of the housing is reduced correspondingly, thereby reducing portability and design. A degree of freedom can be secured.
[0009]
The first and second circuit components that require isolation from each other are mounted with the ground pattern therebetween. For this reason, the first and second circuit components are not only separated from each other by distance, but also good isolation performance can be obtained by the shielding effect by the ground pattern.
[0010]
For example, when circuit components that require electromagnetic isolation are mounted as the first and second circuit components, the signal wiring pattern provided on the opposite surface of the printed wiring board or the inner layer of the multilayer printed wiring board The noise generated in is absorbed by the ground pattern. That is, the ground pattern exhibits an electromagnetic shielding effect, and the electromagnetic isolation performance can be kept high. In addition, when circuit components that require thermal isolation from each other are mounted as the first and second circuit components, the ground pattern functions as a heat radiating member and a heat conducting material, so that the heat generated by the circuit components is localized. Therefore, the thermal characteristics of the first and second circuit components can be improved.
[0011]
The invention is also characterized in that a shield case having a function of shielding at least one of the first and second circuit components and a function of holding the display is installed between the printed wiring board and the display unit. To do.
With this configuration, the first and second circuit components are more effectively electromagnetically separated by the shielding effect of the shield case, and as a result, the isolation characteristics between the circuit components can be further improved. Can do. In addition, since the shield case also functions as a holder for the display unit, the dimension in the thickness direction of the housing can be reduced compared to the case where a dedicated holder is provided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIGS. 1A and 1B show the appearance of a foldable mobile phone that is a first embodiment of a mobile communication terminal according to the present invention, in which FIG. 1A is a front view, FIG. 1B is a side view, c) is a rear view.
[0015]
In this foldable mobile phone, a lower housing 1 and an upper housing 2 are connected via a hinge mechanism 3 so as to be rotatable. A key input unit 11 and a speaker 12 for transmission are provided on the front surface of the lower housing 1, and a battery storage unit is provided on the back surface. On the other hand, a main display 21 made of LCD (Liquid Crystal Devise) and a receiving speaker 22 are arranged on the front surface of the upper housing 2, and a sub-display 24 also made of LCD is provided on the rear surface. In addition, 23 is an antenna and is accommodated in the antenna accommodating part 25 provided in the back cover 2b so that advancement / retraction is possible.
[0016]
By the way, the upper housing 2 is configured as follows. FIG. 2 is an exploded perspective view showing the structure, and FIG. 5 is a cross-sectional view. That is, the display unit 4 is accommodated in a housing composed of the front cover 2a and the back cover 2b. The display unit 4 is integrated with the printed wiring board 41 sandwiched between the main display 21 and the sub display 24.
[0017]
First, the main display 21 has a main LCD unit 210 held by an LCD holder 211 as shown in FIG. 5, and the main LCD holder 211 holding the main LCD unit 210 is fixed to a shield case 214. A shield case 214 is attached to one surface of the printed wiring board 41. Reference numeral 212 denotes a transmission window for the main display 21 provided on the front cover 2a, and 213 denotes a circuit component mounted on one surface of the printed wiring board 41.
[0018]
On the other hand, the sub-display 24 is configured as follows. FIG. 3 is an exploded perspective view showing the structure. That is, the sub display 24 includes a sub LCD unit 43 and a shield case 42. As shown in FIG. 4, the sub LCD unit 43 has a flexible cable 432 connected to the sub LCD 431 and a light guide 433 attached to the back surface of the sub LCD 431. The light guide 433 is attached to the sub LCD 431 using, for example, a double-sided tape.
[0019]
The shield case 42 has a function of shielding the circuit components 412 and 413 mounted on the other surface of the printed wiring board 41 and a function of holding the sub LCD unit 43, and has a frame shape with a hollowed center portion. It consists of members. The sub LCD unit 43 is fixed to the hollowed central portion 421 of the shield case 42. The sub LCD unit 43 is fixed by fitting a plurality of protrusions 434 provided on the outer edge of the sub LCD unit 43 into a plurality of grooves 422 provided on the inner edge of the central portion 421 of the shield case 42 as shown in FIG. It is done by combining.
[0020]
Incidentally, a solid ground pattern 411 is formed at the center of the printed wiring board 41 on the surface where the sub-display 24 is attached, as shown in FIG. The ground pattern 411 is provided at a position facing the sub LCD unit 43, and the shape and size thereof are set to correspond to the shape of the sub LCD unit 43 and slightly larger than that. The ground pattern may be a grid pattern or a stripe pattern, and may be any pattern as long as it is a planar ground pattern.
[0021]
Further, a plurality of circuit components are mounted on the periphery of the ground pattern 411 on the printed wiring board 41 as shown in FIG. The arrangement of these circuit components is set so that the first and second circuit components 412 and 413 that need to be separated electromagnetically and thermally from each other are separated from each other with the ground pattern 411 therebetween. For example, a circuit component including a high-frequency power amplifier is arranged on one side as a first circuit component 412, and a circuit component constituting a high-frequency receiving circuit including a reception intermediate frequency amplifier or the like is a second circuit component 413. Arranged on the other side.
[0022]
Further, the plurality of circuit components mounted on the printed wiring board 41 are separated by a partition wall of the shield case 42 for each group. FIG. 7 shows the configuration, and a two-dot chain line in the drawing indicates the position of the partition wall of the shield case 42.
[0023]
Because of such a configuration, only the ground pattern 411 is formed at a position facing the sub LCD unit 43 on the printed wiring board 41, and circuit components are distributed and mounted on the periphery thereof. For this reason, compared with the case where circuit components are mounted on the entire surface of the printed wiring board 41, the arrangement interval between the printed wiring board 41 and the sub display 42 can be made closer. Further, the central portion 421 of the shield case 42 is cut out and the sub LCD unit 43 is fitted therein so that the sub LCD unit 43 is held. For this reason, the dimension of the thickness direction can be suppressed compared with the case where the holding member and shield case of the sub LCD unit 43 are provided separately. Therefore, according to the present embodiment, it is possible to reduce the thickness of the upper housing 2 and to ensure sufficient portability and design freedom by these synergistic effects.
[0024]
Of the circuit components mounted on the periphery of the printed wiring board 41, the first and second components that need to be isolated from each other electromagnetically and thermally like the relationship between the high frequency power amplifier and the reception intermediate frequency amplifier. The circuit components 412 and 413 are mounted at positions spaced apart from each other with the ground pattern 411 therebetween. Further, the first and second circuit components 412 and 413 are electromagnetically separated by the partition wall of the shield case 42. For this reason, the first and second circuit components 412 and 413 are spaced apart from each other, and good isolation performance can be maintained due to the shielding effect of the ground pattern 411 and the partition wall of the shield case 42. it can.
[0025]
For example, noise generated in a circuit component such as a high-frequency power amplifier is difficult to be transmitted to the circuit component of the receiving circuit system because it is separated in distance and is blocked by the partition wall of the shield case 42. .
[0026]
Further, as shown in FIG. 8, signal wiring patterns 414 and 416 are provided in the inner layer of the multilayer printed wiring board, and noise is generated from these signal wiring patterns 414 and 416. However, noise generated from the signal wiring pattern is effectively absorbed by the ground pattern 411 having a large area. For this reason, the influence of the noise on the peripheral circuit components 412 and 413 is reduced.
[0027]
On the other hand, most of the heat generated by the high-frequency power amplifier is transmitted to the ground pattern 411 having a large area provided in the vicinity thereof, and is radiated from the ground pattern 411. For this reason, the problem that the heat generated by the high-frequency power amplifier is accumulated in the peripheral portion and locally becomes hot is avoided, thereby reducing adverse effects on the peripheral circuit components as well as the high-frequency power amplifier itself. Is done.
[0028]
In addition, discomfort due to heat generated by the user is reduced. That is, as shown in FIG. 1A and FIG. 2, the upper housing 2 is provided with a speaker 22 for receiving a call, and the user makes a call with the speaker 22 touching or approaching the ear. Do. For this reason, heat generated from the circuit component 412 such as a high-frequency power amplifier is transmitted to the user's ear during a call, giving the user an unpleasant feeling. However, in the present embodiment, heat generated by the heat generating circuit component 412 is transmitted to the planar ground pattern 411 and is radiated from the ground pattern 411. For this reason, the temperature rise in the vicinity of the speaker 22 can be suppressed, thereby reducing the user's discomfort.
[0029]
Further, in this embodiment, as described above, the plurality of protrusions 434 provided on the outer edge of the sub LCD unit 43 are fitted into the plurality of grooves 422 provided on the inner edge of the central portion 421 of the shield case 42. As a result, the sub LCD unit 43 is fixed to the shield case 42. For this reason, it becomes possible to fix the sub LCD unit 43 simply, with high accuracy and stably, thereby maintaining high reliability of the terminal and further improving the assembly workability.
[0030]
(Second Embodiment)
In the second embodiment of the present invention, a concave portion is provided at a position facing the sub LCD unit of the printed wiring board, a planar ground pattern is formed on the bottom surface of the concave portion, and the concave portion on the printed wiring board is separated. Circuit components that require electromagnetic and thermal isolation at positions are mounted separately.
[0031]
FIG. 9 is a cross-sectional view showing the configuration of the upper casing of a foldable mobile phone which is the second embodiment of the mobile communication terminal according to the present invention. In the figure, the same parts as those in FIG.
[0032]
A concave portion 417 is provided in the central portion on the surface where the sub-display 24 of the printed wiring board 41 ′ is attached. The concave portion 417 is provided at a position facing the sub LCD unit 43, and the shape and size thereof are set to correspond to the shape of the sub LCD unit 43 and slightly larger than that. A solid ground pattern 411 is formed on the bottom surface of the recess 417. The ground pattern may be a grid pattern or a stripe pattern, and may be any pattern as long as it is a planar ground pattern.
[0033]
A plurality of circuit components are mounted on the periphery of the concave portion 417 on the printed wiring board 41 '. As shown in FIG. 7, these circuit components are arranged in a ground pattern in which first and second circuit components 412 and 413 that need to be separated from each other electromagnetically and thermally are formed on the bottom surface of the recess 417. 411 is set to be spaced apart from each other.
[0034]
A shield case 42 'to which the sub LCD unit 43 is fixed is attached to the printed wiring board 41'. At this time, the bottom surface of the central portion of the shield case 42 ′ is positioned so as to contact the ground pattern 411 in the recess 417.
[0035]
With such a configuration, in the state where the shield case 42 'is attached to the printed wiring board 41', the height of the shield case 42 'corresponds to the depth of the recess 417 provided in the printed wiring board 41'. Lower by minutes. For this reason, the thickness of the back cover 2b ′ of the upper casing 2 is further reduced, and as a result, the upper casing 2 can be further reduced in thickness.
[0036]
Also in the second embodiment, among the circuit components mounted on the peripheral portion of the printed wiring board 41 ', electromagnetic and thermal mutuals are obtained as in the relationship between the transmitting high frequency power amplifier and the receiving intermediate frequency amplifier. In particular, circuit components 412 and 413 that require isolation are mounted at positions spaced apart from each other with the ground pattern 411 therebetween. Moreover, these circuit components 412 and 413 are electromagnetically separated by the partition wall of the shield case 42 '. For this reason, the circuit components 412 and 413 are spaced apart from each other, and good isolation performance can be maintained due to the shielding effect of the ground pattern 411 and the partition wall of the shield case 42 '.
[0037]
(Other embodiments)
In each of the embodiments described above, the ground pattern 411 is formed at the center of the printed wiring board 41, 41 'corresponding to the position of the sub LCD unit, and the circuit components 412 and 413 that need to be isolated from each other at the periphery. Implemented.
[0038]
However, in some mobile communication terminals, the sub-display is installed in a direction orthogonal to the longitudinal direction of the upper casing, that is, in a horizontal direction. In this case, corresponding to the orientation of the sub-display, for example, as shown in FIG. 11, a printed circuit board 41 is formed with a ground pattern 411 'in the horizontal direction, and a plurality of circuit components that require isolation from each other. 412 'and 413' are mounted across the ground pattern 411 '. Even in this configuration, it is possible to reduce the thickness of the housing and maintain the isolation performance between the circuit components 412 ′ and 413 ′.
[0039]
In the above embodiment, the folding type mobile phone has been described as an example. However, the present invention can also be applied to a mobile communication terminal of a type in which the first and second housings are opened and closed by sliding with a slide mechanism. The present invention is also applicable to a straight type mobile communication terminal composed of a single casing.
[0040]
Other types and structures of mobile communication terminals, sub-display installation positions and corresponding ground pattern formation positions, ground pattern shapes and sizes, types of circuit components that require mutual isolation and their arrangement The installation position, shield case structure, and the like can be variously modified and implemented without departing from the scope of the present invention.
[0041]
【The invention's effect】
As described above in detail, according to the present invention, there is provided a mobile communication terminal in which a printed wiring board on which circuit components are mounted and a display unit are housed in a casing, and the display on the printed wiring board. A planar ground pattern is formed on a portion facing the unit, and the first and second portions on one surface of the printed wiring board are separated from each other by electromagnetic or thermal isolation. The first and second circuit components that are required to be mounted separately , and at least one of the first and second circuit components is shielded between the printed wiring board and the display unit, and the display The shield case having the function of holding the unit is configured to be installed in a state of being in electrical contact with the ground pattern .
[0042]
Therefore, according to the present invention, it is possible to provide a mobile communication terminal capable of maintaining good communication quality by reducing the interference between circuit components while reducing the thickness of the housing.
[Brief description of the drawings]
1A and 1B show the appearance of a foldable mobile phone as a first embodiment of a mobile communication terminal according to the present invention, in which FIG. 1A is a front view, FIG. 1B is a side view, and FIG. Figure.
2 is an exploded perspective view showing a configuration of an upper housing of the folding cellular phone shown in FIG. 1. FIG.
3 is an exploded perspective view showing a configuration of a sub-display provided in the upper housing shown in FIG. 2. FIG.
4 is an exploded perspective view showing a configuration of a sub LCD unit of the sub display shown in FIG. 3;
FIG. 5 is a cross-sectional view of the upper housing portion of the folding mobile phone shown in FIG. 1;
6 is an enlarged view showing a main part of the upper housing part shown in FIG. 5. FIG.
7 is a plan view showing a configuration of a printed wiring board provided in the upper housing shown in FIG. 2. FIG.
8 is a partial cross-sectional view showing the configuration of a printed wiring board provided in the upper housing shown in FIG.
FIG. 9 is a cross-sectional view showing a configuration of an upper casing of a folding cellular phone which is a second embodiment of the mobile communication terminal according to the present invention.
10 is a plan view showing the configuration of the printed wiring board shown in FIG. 9. FIG.
FIG. 11 is a plan view showing a configuration of a printed wiring board according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Lower housing | casing 2 ... Upper housing | casing 2a ... Front cover 2b ... Back cover 3 ... Hinge mechanism 4 ... Display unit 11 ... Key input part 12 ... Transmitting microphone 21 ... Main display 22 ... Receiving speaker 23 ... Antenna 24 ... Sub-display 25 ... Antenna housing parts 41, 41 '... Printed wiring boards 42, 42' ... Shield case 43 ... Sub LCD unit 210 ... Main LCD
211 ... LCD holder 212, 213 ... transparent window 214 ... shield case 411,411 ', 415 ... grounding pattern 213,412,412', 413,413 '... circuit component 414,416 ... signal wiring pattern 417 ... concave 421 ... cutting The extracted central part 422 ... groove 431 ... sub LCD
432 ... Flexible cable 433 ... Light guide 434 ... Projection

Claims (2)

A mobile communication terminal in which a printed wiring board on which circuit components are mounted and a display unit are accommodated in a housing,
Forming a ground pattern forming the planar at a site opposite to the display unit of the printed wiring board,
The first and second circuit components that need to be separated electromagnetically or thermally from each other are separately mounted on the first and second portions across the ground pattern on one surface of the printed wiring board. ,
And a shield case having a function of shielding at least one of the first and second circuit components and a function of holding the display unit between the printed wiring board and the display unit. A mobile communication terminal characterized by being installed in an electrically contacted state . The mobile communication terminal according to claim 1, wherein the ground pattern is set so that a shape and a size correspond to and are larger than a shape of the display unit.

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