JP4667831B2 - Communication terminal - Google Patents

Description

  The present invention relates to a communication terminal in which a liquid crystal display unit disposed in an opening of a housing is covered with a protective cover.

As a typical communication terminal provided with a liquid crystal display unit, there is a mobile phone. For example, a foldable mobile phone that forms a hinge portion that can be rotated by a hinge of an upper housing and a hinge of a lower housing is provided with a liquid crystal display portion on a surface (referred to as a back surface) that is overlapped when the upper housing is folded in two. A receiving part is provided, and an operating part is provided on the back surface of the lower casing and a transmitting part is provided.
In this foldable mobile phone, the upper case and the lower case are opened during a call so that the earpiece and mouthpiece can be separated from each other by the distance between the ear and the mouth, and when not in use, it is folded in half so that it is almost half Miniaturized to size.

The liquid crystal display unit is provided so as to be exposed from the opening of the upper housing, and a communication unit, a circuit board, and the like are stacked and disposed behind the liquid crystal display unit. A resin protective panel is provided in the opening of the upper casing, and the protective panel protects the display surface of the liquid crystal display device.
However, since the protective panel is made of resin, it is easily charged, the inner surface is charged by the communication unit and the circuit board, and the outer surface is charged by static electricity generated by contact with the ear or the like. The distribution of static electricity in this protective cover is not uniform, and polarized charges tend to concentrate on the periphery.
When the potential difference of such non-uniform distribution increases, a short circuit occurs. However, if the path is from the protective panel to the liquid crystal display unit, the liquid crystal display unit may be destroyed.

For example, in the electrostatic breakdown prevention panel disclosed in Patent Document 1 below, a pattern made of conductive ink is provided on the surface of the plastic panel base 3 covering the display 1 as shown in FIG. Print 5 was applied along the periphery of the display window and conducted to the metal chassis.
Further, in the structure of the liquid crystal display watch disclosed in Patent Document 2 below, as shown in FIG. 6, printing 11 is performed with conductive ink on the periphery of the cover glass 9 excluding the central portion 7 where the diode is located, The static electricity generated in the glass 9 is short-circuited at the periphery where the diode is not located, thereby preventing a circuit failure.

Sho 61-292897 Sho 54-145577

However, in the structures of the conventional electrostatic breakdown prevention panel and the liquid crystal display watch described above, conductive printing is formed on the periphery of the panel base material and the cover glass in an annular shape. It acts as a frame-type antenna (loop antenna) that induces an electromotive force by the radiated magnetic field, which may affect the transmission / reception operation of the communication unit.
The present invention has been made in view of the above situation, and provides a communication terminal capable of protecting a liquid crystal display unit from a short circuit of static electricity without affecting the transmission / reception operation of the communication unit, thereby improving the reliability of the communication terminal. With the goal.

  To achieve the above object, a communication terminal according to the present invention includes a housing, a radio unit and a circuit board accommodated in the housing, and a liquid crystal display unit connected to the circuit board and disposed in an opening of the housing. And a protective cover made of resin that covers the liquid crystal display portion so that it can be seen through, and a conductive layer is provided on a peripheral portion of the protective cover, and the conductive layer is not continuous in an annular shape. .

In this communication terminal, since the conductive layer provided on the protective cover is not continuous in a ring shape, the conductive layer does not function as a frame-type antenna (loop antenna) that induces an electromotive force by a radiation magnetic field. . As a specific form that is not continuous in a ring shape, for example, C-shaped printing is exemplified. In this case, if the C-shaped gap is too narrow, an electromotive force is induced to affect the wireless performance, and conversely if the gap is too wide, the risk of a short circuit therebetween increases.
Therefore, although the gap depends on the potential difference, when the communication terminal is a mobile phone, it is preferable to set the gap within a predetermined value range as described later.

  According to the communication terminal according to the present invention, the radio unit and the circuit board housed in the housing, the liquid crystal display unit connected to the circuit board and disposed in the opening of the housing, and the resin that covers the liquid crystal display unit in a transparent manner The protective cover is made of, and the conductive layer is provided on the periphery of the protective cover, and the conductive layer is not continuous in an annular shape, so the conductive layer does not act as a frame-type antenna, There is no possibility of affecting the transmission / reception operation of the communication unit. As a result, the liquid crystal display unit can be protected from static electricity short circuit without affecting the transmission / reception operation of the communication unit, and the reliability of the communication terminal can be improved.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a communication terminal according to the invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a mobile phone which is a communication terminal according to the present invention.
In a mobile phone (foldable mobile phone) 100 as a communication terminal, a casing 21 includes an upper housing 23 and a lower housing 25, and the upper housing 23 and the lower housing 25 are provided on both hinges 27a. , 27b, which can be folded in half.

A liquid crystal display unit 29 and a receiver unit 31 are provided on the back surface of the upper housing 23. On the back surface of the lower housing 25, an operation unit 33 and a transmission unit 35 are provided.
In addition, the housing 21 is provided with an antenna (not shown), a camera unit, a removable exterior cover, and the like.

FIG. 2 is a cross-sectional view of the upper casing of the mobile phone shown in FIG.
The upper housing 23 is formed by fitting a front case 37 and a back case 39, and the back case 39 is provided with a circuit board 41 and a liquid crystal display unit 29 from the inside. The circuit board 41 is provided with a wireless unit 43 (see FIG. 3).
The liquid crystal display unit 29 is exposed from an opening 45 formed on the back surface of the back case 39.

3 is an exploded perspective view of the upper housing shown in FIG.
The liquid crystal display unit 29 includes a liquid crystal panel 47 and an illumination device 49. The illumination device 49 includes a light guide plate made of a transparent resin (not shown). An LED mounted on the circuit board 41 is disposed on the light incident end face of the light guide plate. A reflection sheet (not shown) is disposed on the upper surface (upper surface in FIG. 3) of the light guide plate, and an optical sheet such as a prism plate or a diffusion sheet is disposed on the light emitting surface side.
The reflection sheet, the light guide plate, and the optical sheet are stacked and accommodated in the case. By attaching the circuit board 41 to the case, the LED mounted on the circuit board 41 is positioned on a predetermined light incident end face of the light guide plate.

  The electrodes of the liquid crystal panel 47 are connected to the electrode portions of the circuit board 41 by wiring (not shown). When the circuit board 41 is a flexible board, the electrode of the flexible board and the electrode of the liquid crystal panel 47 may be directly connected via a connector (not shown).

When the LED mounted on the circuit board 41 is turned on, the emitted light enters the light incident end face of the light guide plate, the incident light propagates through the light guide plate as a medium, and part of the light is diffused from the optical sheet. In addition, the light reflected by the reflection sheet also enters the light guide plate, and is also emitted as diffused light from the optical sheet.
Thereby, the light emitted from the illuminating device 49 is transmitted from the back surface of the liquid crystal panel 47 as a backlight, so that the visibility of the liquid crystal display unit 29 is enhanced.

  An opening 45 for exposing the liquid crystal panel 47 is formed in the back case 39, and a step portion 51 (see FIG. 2) is formed on the rear surface side periphery of the opening 45. A resin protective cover 53 is fitted to the stepped portion 51 via a double-sided tape 53a. The protective cover 53 covers the liquid crystal panel 47 so that the liquid crystal panel 47 can be seen through, and protects the liquid crystal panel 47 from external interference (such as rubbing due to contact and adhesion of dirt). Specific examples of the resin for the protective cover 53 include polystyrene, polycarbonate resin, acrylic resin, and ABS resin.

A conductive layer 55 is provided on the periphery of the protective cover 53. In this specification, the peripheral portion refers to the front surface, back surface, end surface, and peripheral edge of the protective cover 53. In the present embodiment, as shown in FIG. 3, a conductive layer 55 is provided on the periphery of the back surface of the protective cover (upper surface in FIG. 3). As shown in FIG. 1, the conductive layer 55 is hidden behind the periphery of the opening 45 and is not visually recognized from the back surface side of the upper housing 23. That is, the liquid crystal display unit 29 is not disturbed by visual recognition. The double-sided tape 53 a described above is selected so that it does not overlap the conductive layer 55 and has a width dimension as small as possible so as not to interfere with the conductive layer 55.
However, the conductive layer 55 is not continuous in an annular shape. That is, a part of the annular shape is divided by the slit 57.
Thus, the conductive layer 55 is formed in a C shape. A plurality of slits 57 may be provided. A plurality of C-shaped conductive layers 55 may be provided concentrically. In short, it is only necessary to be divided by the slit 57 so as not to constitute a frame-type antenna (loop antenna).

The conductive layer 55 is formed by subjecting the protective cover 53 to a conductive material such as aluminum, nickel, chromium, gold, or platinum by vacuum deposition, sputtering, or electroless plating, and applying a photoresist thereon to form a predetermined electrode pattern. After forming a photoresist pattern by exposing the photoresist through the mask, it can be formed by a known method such as a method of etching or mechanically removing the photoresist pattern, or a method of combining them. .
Moreover, you may form the electroconductive layer 55 by screen-printing electroconductive ink. As the conductive ink, it is possible to use a conductive ink prepared by dispersing a metal or conductive metal oxide powder made transparent by micronization in a synthetic resin solvent. As this metal, gold, silver, palladium, zinc, aluminum, or the like can be used. As the metal compound, iridium oxide, zinc oxide, aluminum oxide, or the like can be used.
Further, the conductive layer 55 may be provided by sticking a transparent conductive film having adhesiveness.

Here, the width w of the slit 57 is important so that the conductive layer 55 does not affect the wireless performance and can effectively prevent a short circuit of static electricity.
That is, if the slit 57 is too narrow, the influence on the wireless performance cannot be effectively avoided. Further, if the slit 57 is too wide, there is a problem that a short circuit occurs due to static electricity. In addition, as for the formation width of the slit 57, there are not a few things that deviate from the effective configuration unless the variation due to printing is taken into consideration.

In the case of the protective cover 53 for a cellular phone, it is confirmed that there is no problem in the wireless performance when the width w of the slit 57 is 1 mm or more in consideration of a potential difference generally caused by static electricity. In addition, it was confirmed that if the width w of the slit 57 is 5 mm or less, the possibility of static electricity is greatly reduced.
Therefore, in the present embodiment, the width w of the slit 57 is set to 2 mm in consideration of variations in formation accuracy due to printing or the like. That is, the conductive layer 55 is set with a slit width w that does not cause a problem in terms of wireless performance and electrostatics even when the maximum variation occurs in the printing process.

FIG. 4 is an enlarged cross-sectional view of a main part showing a connection structure between the conductive layer and the circuit board.
The protective cover 53 thus formed with the conductive layer 55 is fixed to the opening 45 of the back case 39 with a double-sided tape, and the sheet metal material or the like is attached with the lighting device 49 and the liquid crystal panel 47 attached. The conductive member 59 is connected to a ground terminal (GND) (not shown) of the circuit board 41.
That is, the conductive member 59 includes a long plate contact portion 59a along one side of the conductive layer 55 and a pair of substrate contact terminal portions 59b and 59b protruding from both longitudinal ends of the long plate contact portion 59a.
As shown in FIG. 4, the conductive member 59 avoids contact with the liquid crystal panel 47 and the lighting device 49 in a state where the circuit board 41, the lighting device 49, the liquid crystal panel 47, and the protective cover 53 are attached. The long plate contact portion 59a is in contact with the conductive layer 55, and the substrate contact terminal portions 59b and 59b are in contact with a ground terminal (not shown) of the circuit board 41.
At this time, the long plate contact portion 59 a of the conductive member 59 contacts a metal sheet 53 b such as a copper foil tape provided on the conductive layer 55 of the protective cover 53. The metal sheet 53b has conductivity with respect to the conductive layer 55 and the long plate contact portion 59a. Thereby, even if the long plate contact part 59a and the electroconductive layer 55 slide relatively, the electroconductive layer 55 can prevent abrasion.

  As a result, the conductive layer 55 of the protective cover 53 is grounded to the circuit board 41 via the conducting member 59, and static electricity charged on the protective cover 53 is removed.

  In this cellular phone 100, the conductive layer 55 provided on the protective cover 53 is not continuous in an annular shape, so that the conductive layer 55 induces an electromotive force by a radiated magnetic field of a radio wave (loop antenna). No longer works.

Therefore, according to the folded-type mobile phone 100 according to the present embodiment, the radio unit and the circuit board 41 accommodated in the housing 21, and the liquid crystal display unit connected to the circuit board 41 and disposed in the opening 45 of the housing 21. 29 and a resin protective cover 53 that covers the liquid crystal display unit 29 so that the liquid crystal display unit 29 can be seen through. A conductive layer 55 is provided around the protective cover 53, and the conductive layer 55 continues in a ring shape. Therefore, the conductive layer 55 does not act as a frame antenna, and there is no possibility of affecting the transmission / reception operation of the communication unit.
As a result, the liquid crystal display unit 29 can be protected from static electricity short circuit without affecting the transmission / reception operation of the communication unit, and the reliability of the mobile phone 100 can be improved.

  In the above embodiment, the case where the communication terminal is the mobile phone 100 has been described as an example. However, the present invention can be applied to other communication terminals such as a cordless phone having a liquid crystal display, a car phone, a mobile TV, a mobile phone, and the like. It can be suitably used for a terminal (handy terminal) or the like, and exhibits the same operations and effects as described above.

It is a perspective view showing the mobile telephone which is a communication terminal which concerns on this invention. It is sectional drawing of the upper housing of the mobile phone shown in FIG. It is a disassembled perspective view of the upper housing shown in FIG. It is a principal part expanded sectional view showing the connection structure of a conductive layer and a circuit board. It is a front view showing the conventional electrostatic breakdown prevention panel in which conductive pattern printing was performed. It is a front view showing the cover glass of the conventional liquid crystal display timepiece which performed printing with the conductive ink in the periphery.

Explanation of symbols

21 Housing 29 Liquid Crystal Display 41 Circuit Board 45 Opening 53 Protective Cover 55 Conductive Layer 100 Mobile Phone (Communication Terminal)

Claims (1)

A housing, a radio unit and a circuit board accommodated in the housing, a liquid crystal display unit connected to the circuit board and disposed in an opening of the housing, and a protective cover made of resin that covers the liquid crystal display unit in a transparent manner And
A conductive layer that is grounded is provided on the periphery of the protective cover, and a slit that is approximately 1 mm to approximately 5 mm is provided in a part of the conductive layer so that the conductive layer is continuous in an annular shape. A communication terminal characterized by not.

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