JP2009194223A - Mobile terminal device and method of grounding mobile terminal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize grounding and liberalize grounding positions in a mobile telephone having a metal casing. <P>SOLUTION: A plurality of conductive rubber members 20a-20e with one end part in contact with a metallic battery cover 1 are provided in a plastic frame portion 2, and the other end part of each of the conductive rubber members 20a-20c is brought into contact with a metal plate 4. Metal spring portions 4R1, 4R2, 4L1, 4L2 provided in the metal plate 4 are brought into contact with grounding points 3L1, 3L2, 3R1, 3R2 formed on a circuit board 3, and the conductive rubber members 20d and 20e are brought into contact with grounding points 3L3 and 3R3 formed on the circuit board 3. Since the conductive rubber members are compressed with appropriate pressure when the battery cover 1 is mounted, grounding is stabilized. By bringing the battery cover 1 and the grounding points into contact with each other via the conductive rubber members and the metal plate 4, the positions of the conductive rubber members and the positions of the metal spring portions can be set separately, resulting in liberalization of grounding positions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mobile phone, a PHS phone (PHS: Personal Handyphone System), a PDA device (PDA: Personal Digital Assistant), a portable game machine, a digital camera device, a notebook type, and the like. The present invention relates to a portable terminal device suitable for application to personal computer devices and the like, and a grounding method for the portable terminal device. In particular, a grounding space required is reduced by bringing a housing formed of a conductive member into contact with a grounding point on a circuit board via a conductive rubber member and an intermediate conductive member, thereby reducing the size of the device. The present invention also relates to a portable terminal device and a grounding method for the portable terminal device that enable obtaining good antenna characteristics.

  In recent years, many mobile phones using a metal casing have been seen. However, since the metal casing has conductivity, the antenna characteristics are adversely affected as it is. For this reason, when a metal casing is used, it is necessary to prevent the disadvantage that adversely affects the antenna characteristics by bringing the metal casing into contact with a ground point on the circuit board.

  Japanese Patent Laid-Open No. 2000-251972 discloses a patent document (Patent Document 1) that stabilizes the contact between a metal housing and a grounding point of a printed circuit board without reducing the component mounting area of the printed circuit board, thereby improving wireless performance (antenna characteristics). The boss mounting structure of the portable wireless device that prevents the deterioration of the above is disclosed.

  In the case of the boss mounting structure of this portable wireless device, it is fixed to the boss of the metal casing, and is formed so as to contact the seat surface of this boss and the ground pattern (ground point) of the printed circuit board with spring pressure. A metal spring is interposed between the boss of the metal housing and the ground point of the printed circuit board. And a printed circuit board and a lower case are fastened and fixed to the boss | hub which attached this metal spring with a screw | thread. As a result, even when the screw is loosened, the elasticity of the metal spring can maintain the contact between the metal housing and the grounding point of the printed circuit board, and the metal housing and the grounding point of the printed circuit board are not in contact with each other. As a result, it is possible to prevent inconvenience that the wireless performance is deteriorated.

Japanese Unexamined Patent Publication No. 2000-251972 (Page 4, FIGS. 1 and 2)

  However, in the case of the boss mounting structure of the portable wireless device disclosed in Patent Document 1 described above, when the position of the boss provided on the metal housing side is viewed as a subject, the position of the boss provided on the metal housing side is It is limited to the position of the ground point provided on the printed circuit board side. On the other hand, when the position of the grounding point of the printed circuit board is viewed as a subject, the position of the grounding point of the printed circuit board is limited to the position of the boss provided on the metal housing side. For this reason, there is a problem that the degree of freedom in designing the device is limited to the position of the boss and the position of the grounding point of the printed circuit board, making it difficult to design the device.

  In addition, since the size of the boss provided on the metal housing side becomes the size of the grounding point, the grounding point inevitably increases. For this reason, when a large number of bosses are provided in the metal casing, the number of grounding points increases, so that the total area of the grounding points increases, resulting in a problem that hinders downsizing of the equipment. . On the other hand, when the number of bosses provided in the metal casing is reduced, the number of grounding points is reduced, which causes a problem that the adverse effect of the metal casing on the antenna characteristics cannot be prevented.

  Further, since the metal spring is formed by cutting out the sheet metal, the edge portion may be sharp. For this reason, even if a user touches, there is a problem that a troublesome processing such as cutting the edge portion of the metal spring into a round shape is necessary so as not to be injured. Furthermore, when the user touches and deforms the metal spring, there is a problem that it is difficult to achieve stable contact between the metal housing and the grounding point of the printed circuit board.

The present invention has been made in view of the above problems,
1. Without hindering the freedom of design
2. The total area of the grounding point can be reduced to reduce the size of the equipment.
3. The metal housing can prevent inconvenience that adversely affects the antenna characteristics,
4). Troublesome processing such as cutting the edge part round can be made unnecessary,
5. Even if the user touches, the user is not injured,
6). An object of the present invention is to provide a portable terminal device capable of maintaining a stable contact relationship with a grounding point, and a grounding method for the portable terminal device.

The mobile terminal device according to the present invention is
A housing formed of a conductive member;
A circuit board housed in the housing;
A plurality of ground points provided at predetermined locations on the circuit board;
An intermediary conductive member having a contact portion that contacts a ground point on the circuit board;
A plurality of conductive rubber members provided such that one end portion contacts the casing and the other end portion contacts the intermediate conductive member.

  And the said subject is solved by earth | grounding the housing | casing formed with the said electrically-conductive member to the earthing | grounding point on the said circuit board via the said contact part of the said electrically-conductive rubber member and the said mediation electrically-conductive member.

Further, the grounding method of the mobile terminal device according to the present invention is a grounding method of the mobile terminal device in which a circuit board having a plurality of grounding points is housed in a housing formed of a conductive member,
The conductive rubber member is formed of the conductive member by bringing one end of the conductive rubber member into contact with the housing and the other end of the conductive rubber member into contact with an intermediate conductive member having a plurality of contact portions that are in contact with the ground points of the circuit board. The above-described problem is solved by grounding the casing to the ground point on the circuit board via the contact portion of the conductive rubber member and the intermediate conductive member.

  In the present invention as described above, an intermediate conductive member having a contact portion in contact with each ground point is interposed between the housing formed of the conductive member and the ground point on the circuit board. Then, by bringing the other end portion of the conductive rubber member provided so that one end portion is in contact with the housing into contact with the intermediate conductive member, the conductive rubber member and the intermediate conductive member are interposed through the contact portion. Ground the enclosure to a ground point on the circuit board.

  According to the present invention, contact between the housing and the ground point on the circuit board is achieved through the intermediate conductive member. For this reason, it is possible to set the position where contact between the casing formed of the conductive member and the intermediate conductive member and the position where the intermediate conductive member and the grounding point on the circuit board are contacted separately, respectively. . As a result, the position of the conductive rubber member that makes contact between the housing and the intermediate conductive member can be freely set by the designer, and the position of the contact portion that makes contact between the intermediate conductive member and the ground point on the circuit board. Can also be the freedom of the designer. Therefore, the design of the mobile terminal device can be facilitated.

  In addition, the conductive rubber comes into contact with the housing formed of the conductive member and the intermediate conductive member whose contact portion is in contact with the ground point on the circuit board in a small space. For this reason, each ground space can be made into a very small ground space, and even when a large number of ground spaces are provided, the area on the mobile phone that is eroded by the ground space can be reduced (= The total grounding space can be reduced.) Moreover, since the grounding space can be made small by using the conductive rubber member, the position where the grounding space is provided can be made almost free. Therefore, it can contribute to miniaturization of equipment.

  Further, a housing formed of a conductive member and an intermediate conductive member whose contact portion is in contact with a ground point on the circuit board are brought into contact with each other via a conductive rubber member. Since the conductive rubber member has elasticity, the conductive rubber member is compressed by an appropriate pressure when the casing is screwed or the like, and is in close contact with the casing and the intermediate conductive member. Thus, the ground point on the housing and the circuit board can be stably brought into contact with each other through the contact portion of the conductive rubber member and the intermediate conductive member. Therefore, when an antenna is provided in a device to which the present invention is applied, stable antenna characteristics can be obtained.

  Further, the conductive rubber member is a soft member having elasticity, and does not have a sharp edge portion like a metal spring. For this reason, it is possible to prevent inconvenience that the user touches and is injured. Moreover, in order to prevent a user's injury, the troublesome process of cutting an edge part roundly etc. can be made unnecessary.

  In addition, since the conductive rubber member is an elastic member, even when the user touches and deforms, the conductive rubber member can be immediately restored to the original shape, and stable contact with the housing and the intermediate conductive member can be maintained. Therefore, stable contact between the housing and the ground point on the circuit board can be achieved.

  The present invention can obtain the following effects.

  1. It is possible to allow a designer to design a substantially free device without hindering the degree of freedom of device design.

  2. The total area of the ground point can be reduced, and the size of the device can be reduced.

  3. In the case where an antenna is provided in a device to which the present invention is applied, it is possible to prevent an inconvenience that a housing formed of a conductive member adversely affects antenna characteristics.

  4). The conductive rubber member is a soft member having elasticity, and since there is no sharp edge portion such as a metal spring, a troublesome processing such as cutting the edge portion round can be eliminated.

  5). The conductive rubber member is a soft member having elasticity, and since there is no sharp edge portion such as a metal spring, it is possible to prevent the user from being injured when touched by the user.

  6). Since the conductive rubber member is an elastic member, even when the user touches and deforms, the conductive rubber member can immediately return to the original shape and maintain stable contact with the housing and the intermediate conductive member. . Therefore, a stable contact relationship between the housing and the ground point on the circuit board can be maintained.

  The present invention can be applied to a mobile phone.

[Configuration of mobile phone]
The mobile phone according to the embodiment to which the present invention is applied is a so-called straight type mobile phone as shown in FIG. FIG. 1 is a perspective view of the mobile phone as viewed from the back side with the front panel on the front side (the side where the display unit is provided) of the straight type mobile phone removed. As can be seen from FIG. 1, in addition to the front panel, the mobile phone of this embodiment includes a conductive member such as a metal member typified by aluminum, stainless steel, and titanium. And a plastic frame portion 2 formed of a plastic member such as ABS resin (acrylonitrile, butadiene (Butadiene), styrene (Styrene) copolymer synthetic resin).

  FIG. 2 is an exploded perspective view of the mobile phone with the front panel removed. As can be seen from FIG. 2, a circuit board 3 and a metal plate 4 formed of a metal member such as aluminum or stainless steel are accommodated in the plastic frame portion 2.

  FIG. 3 is a view of the circuit board 3 as viewed from the back surface portion 3a side (= a view as viewed from the surface portion opposite to the surface portion on which the display portion is provided). As can be seen from FIG. 3, the circuit board 3 has a substantially rectangular shape as a whole, and is housed in the plastic frame portion 2 and then passed through the screw holes 11 provided at the four corners. The plastic frame portion 2 is screwed.

  On the back surface portion 3a of the circuit board 3, a camera unit 12 and a speaker unit 13 are provided at positions close to the upper end portion 3b. Further, a battery connection terminal 17 for connecting to a battery is provided on the back surface portion 3a of the circuit board 3.

  Further, on the back surface portion 3a of the circuit board 3, grounding points 3R1, 3R2, and 3R3 are provided at predetermined positions on a substantially straight line along the right side surface portion 3c at positions close to the right side surface portion 3c. It has been. Similarly, the ground points 3R1, 3R2, and 3R3 are provided at predetermined positions on a substantially straight line along the right side surface portion 3b at positions close to the right side surface portion 3b. Similarly, on the back surface portion 3a of the circuit board 3, grounding points 3L1, 3L2, and 3L3 are provided at predetermined positions on a substantially straight line along the left side surface portion 3d at positions close to the left side surface portion 3d. Is provided.

  FIG. 4 is a view of the metal plate 4 as viewed from the back surface portion 4a side (= a view as viewed from the surface opposite to the circuit board 3). As shown in FIG. 4, the metal plate 4 has a substantially rectangular shape whose overall shape can be accommodated in the plastic frame portion 2, and the metal plate 4 is located at a position close to the right end and the left end of the upper end portion 4b. 4 have connecting end portions 14 and 15 projecting along the longitudinal direction. Further, the metal plate 4 has a connection end portion 16 that protrudes along the longitudinal direction of the metal plate 4 at a position close to the left end of the lower end portion 4c. Each of these connection end portions 14 to 16 comes into contact with each conductive rubber member fitted in the plastic frame portion 2, and will be described in detail later.

  The metal plate 4 is provided with metal spring portions 4R1 and 4R2 on a straight line along the longitudinal direction of the metal plate 4 at a position close to the right side surface portion 4d. Similarly, the metal plate 4 is provided with metal spring portions 4L1 and 4L2 on a straight line along the longitudinal direction of the metal plate 4 at a position close to the left side surface portion 4e.

Each metal spring portion 4R1, 4R2, 4L1, 4L2 is formed by cutting out the metal plate 4 so as to form a substantially rectangular tongue side portion, and this tongue side portion is shown in FIGS. 5 (a) and 5 (b). As shown in FIG. 3, the substrate is bent so as to protrude toward the circuit board 3 side. As will be described later, when each metal spring portion 4R1, 4R2, 4L1, 4L2 is housed in the plastic frame portion 2, each ground point 3R1, 3R2, 3L1, Alternatively, it comes into contact with 3L2.

[Cell phone assembly process]
Next, an assembling process of such a mobile phone will be described. When assembling this cellular phone, first, the conductive rubber members 20a to 20e are inserted into the insertion holes for the conductive rubber member provided in the plastic frame portion 2 shown in FIG. The fitting hole for the conductive rubber member of the plastic frame portion 2 is formed on the connection end portions 14 to 16 of the metal plate 4 when the metal plate 4 is mounted on the plastic frame portion 2. The conductive rubber members 20a to 20c fitted in the fitting holes are provided at positions where they contact each other. Further, the insertion holes for the conductive rubber member of the plastic frame portion 2 are electrically connected to the ground points 3R3 and 3L3 of the circuit board 3 shown in FIG. 3 when the circuit board 3 is mounted on the plastic frame portion 2. The conductive rubber members 20d to 20e fitted in the fitting holes for the rubber member are provided at positions where they contact each other.

  Each of the conductive rubber members 20a to 20e is a conductive rubber member formed by mixing a conductive member such as a metal into the rubber member. As shown in FIG. 6A, each conductive rubber member 20a to 20e is one end of an insertion post portion 21 having substantially the same diameter as the diameter of the fitting hole 25 for each conductive rubber member provided in the plastic frame portion 2. A flange portion 22 having a diameter larger than that of the insertion post portion 21 is provided on the portion so as to be coaxial. On the surface 22a side of the flange portion 22 opposite to the surface portion on which the insertion strut portion 21 is provided, a contact column portion 23 having a diameter smaller than the diameter of the insertion strut portion 21 is coaxial. Is provided. In addition, an abutting column portion 24 having a diameter smaller than the diameter of the insertion column portion 21 is coaxial with an end portion 21a on the opposite side to the end portion to which the flange portion 22 is connected. It is provided to become.

  When each of the conductive rubber members 20a to 20e is attached to the plastic frame portion 2, the conductive rubber member insertion holes 25 provided in the plastic frame portion 2 as shown in FIG. The insertion support column 21 of each conductive rubber member 20a to 20e is inserted. As a result, as shown in FIG. 6B, the insertion struts 21 of the conductive rubber members 20a to 20e close the fitting holes 25 for the conductive rubber members of the plastic frame portion 2 without gaps, and The conductive rubber members 20a to 20e are attached to the plastic frame portion 2 so that the flange portions 22 of the conductive rubber members 20a to 20e cover the fitting holes 25.

  As described above, the contact post portions 23 and 24 of the conductive rubber members 20a to 20e mounted on the plastic frame portion 2 are ground points on the battery lid 1 and the circuit board 3 formed of a conductive member such as a metal member. (3R1-3R3, 3L1-3L3) and the connection end (14-16) of the metal plate 4 will be in contact with either one, but will be described in detail later.

  Next, in a state where the conductive rubber members 20a to 20e are mounted on the plastic frame portion 2 as described above, the metal plate 4 is mounted on the plastic frame portion 2 as shown in FIG. The mounting position of the metal plate 4 on the plastic frame portion 2 is a mounting position where the conductive rubber members 20a to 20c mounted on the plastic frame portion 2 are in contact with the connection end portions 14 to 16 of the metal plate 4, respectively. .

  When the metal plate 4 is attached to the plastic frame portion 2, the conductive rubber members 20 a to 20 c have elasticity, so that the conductive rubber members 20 a to 20 c abut against the connection end portions 14 to 16 of the metal plate 4. Due to the moderate pressure applied in the step, the contact post portions 23 of the respective conductive rubber members 20a to 20c are crushed, and the respective conductive rubber members 20a to 20c are stabilized with respect to the connection end portions 14 to 16. Contact is made in the state.

  FIG. 7 shows a plan view of the plastic frame portion 2 as viewed from the side where the battery lid 1 is mounted in a state where the conductive rubber members 20a to 20e and the metal plate 4 are mounted. As can be seen from FIG. 7, when the conductive rubber members 20 a to 20 e and the metal plate 4 are attached to the plastic frame portion 2, the plastic frame portion 2 is proximate to the right side surface portion 2 a of the plastic frame portion 2. The conductive rubber member 20b in contact with the connection end 15 of the metal plate 4, the metal spring portion 4L1 of the metal plate 4, the metal spring portion 4L2 of the metal plate 4, and the connection of the metal plate 4 on a substantially straight line along the direction. The conductive rubber member 20c in contact with the end portion 16 and the conductive rubber member 20e in contact with the ground point 3R3 on the circuit board 3 are arranged in parallel at predetermined intervals.

  In addition, when the conductive rubber members 20a to 20e and the metal plate 4 are attached to the plastic frame part 2, the plastic frame part 2 is close to the left side surface part 2b of the plastic frame part 2 and is substantially straight along the longitudinal direction of the plastic frame part 2. The conductive rubber member 20a in contact with the connection end 14 of the metal plate 4, the metal spring portion 4R1 of the metal plate 4, the metal spring portion 4R2 of the metal plate 4, and the ground point 3L3 on the circuit board 3 are contacted. The conductive rubber members 20d are arranged in parallel at predetermined intervals.

  Next, the plastic frame in a state in which the conductive rubber members 20a to 20e and the metal plate 4 are mounted so that the grounding points 3R1 to 3R3 and 3L1 to 3L3 described with reference to FIG. The circuit board 3 is attached to the part 2 and the circuit board 3 is screwed to the plastic frame part 2 through the screw holes 11 shown in FIG.

  As shown in FIG. 2, the plastic frame portion 2 is provided with a camera protection window portion 26 formed of a transparent member such as a plastic member or a glass member, and a plurality of sound emission holes 27. When the circuit board 3 is screwed to the frame 2, the camera unit 12 provided on the circuit board 3 can be seen through the camera protection window 27 and the sound emission hole 27 is interposed. Thus, the speaker unit 13 provided on the circuit board 3 can be seen.

  Further, when the circuit board 3 is screwed to the plastic frame part 2, the metal spring parts 4L1, 4L2 of the metal plate 4 attached to the plastic frame part 2 are respectively connected to the ground points 3R1, 3R2 on the circuit board 3. At the same time, the metal spring portions 4R1, 4R2 of the metal plate 4 are in contact with the ground points 3L1, 3L2 on the circuit board 3, respectively. When the circuit board 3 is screwed to the plastic frame part 2, the conductive rubber members 20d and 20e attached to the plastic frame part 2 come into contact with the ground points 3L3 and 3R3 on the circuit board 3, respectively.

  The metal spring portions 4R1, 4R2, and 4L1, 4L2 of the metal plate 4 are tongue portions formed by cutting out a part of the metal plate 4 as described with reference to FIGS. Are formed by bending, and each has elasticity. For this reason, the metal spring portions 4R1, 4R2, and 4L1, 4L2 that are in contact with the ground points 3R1, 3R2, and 3L1, 3L2 on the circuit board 3 are connected to the ground points 3R1, 3R2, 3L1, 3L2 by the elasticity. Are in contact with each other with an appropriate pressure. Thus, stable contact between the metal spring portions 4R1, 4R2 and 4L1, 4L2 of the metal plate 4 and the ground points 3R1, 3R2, 3L1, and 3L2 on the circuit board 3 is achieved.

  Further, since the conductive rubber members 20d and 20e are also elastic, the grounding points 3L3 and 3R3 on the circuit board 3 are caused by an appropriate pressure applied by screwing the circuit board 3 to the plastic frame portion 2 with screws. The contact pillar portions 23 (see FIGS. 6A and 6B) of the respective conductive rubber members 20d and 20e that are in contact with each other are crushed. Accordingly, stable contact between the conductive rubber members 20d and 20e provided on the plastic frame portion 2 and the ground points 3L3 and 3R3 on the circuit board 3 is achieved.

  Next, when the circuit board 3 is screwed to the plastic frame portion 2, the battery connection terminal 17 shown in FIG. 2 is exposed from the battery housing portion 18 of the plastic frame portion 2. For this reason, the battery is stored in the battery storage portion 18 in a state where a battery (not shown) is electrically connected to the battery connection terminal 17.

And in the state which accommodated the battery in this battery accommodating part 18, the camera provided in each position of the camera protection window part 26 and the some sound emission hole part 27 of the plastic frame part 2, and the metal battery lid 1 The positions of the hole portion 31 and the sound emitting hole portion 32 are aligned, and the battery lid 1 is fitted into the plastic frame portion 2. After that, by attaching a front panel (not shown) to the plastic frame part 2, the assembly process of the mobile phone is completed, but this description is omitted.

[Function of conductive rubber member and metal plate]
Here, as described with reference to FIGS. 6 and 7, the contact column portion 24 of each of the conductive rubber members 20 a to 20 e protrudes from the surface of the plastic frame portion 2 facing the battery lid 1. ing. For this reason, when the battery lid 1 is attached to the plastic frame portion 2, the battery lid 1 comes into contact with the contact column portions 24 of the respective conductive rubber members 20 a to 20 e protruding from the plastic frame portion 2. Become. The battery lid 1 is fitted with the plastic frame portion 2 to apply an appropriate pressure to the conductive rubber members 20a to 20e that are in contact with each other. For this reason, the contact post 24 of each of the conductive rubber members 20a to 20e is brought into contact with the battery lid 1 in such a manner that it is crushed by the appropriate pressure. Thereby, each conductive rubber member 20a-20e can be made to contact stably with respect to the battery cover 1. FIG.

  On the other hand, as described with reference to FIG. 2, among the conductive rubber members 20a to 20e attached to the plastic frame portion 2, the conductive rubber member 20d is at the ground point 3L3 of the circuit board 3, and the conductive rubber member 20e is at the circuit. Each is in direct contact with the ground point 3R2 of the substrate 3. Of the conductive rubber members 20 a to 20 e mounted on the plastic frame portion 2, the conductive rubber members 20 a to 20 c are in contact with the connection end portions 14 to 16 of the metal plate 4, respectively. The metal spring part 4R1 is at the ground point 3L1 of the circuit board 3, the metal spring part 4R2 is at the ground point 3L2 of the circuit board 3, the metal spring part 4L1 is at the ground point 3R1 of the circuit board 3, and the metal spring part 4L2 is at the circuit board 3 Are in contact with the grounding point 3R2.

  That is, the conductive rubber member 20d directly contacts the ground point 3L3 of the circuit board 3, and the conductive rubber member 20e directly contacts the ground point 3R2 of the circuit board 3, whereas the conductive rubber members 20a to 20c are metal. By making contact with the connection end portions 14 to 16 of the plate 4, the ground points 3L1, 3L2, and 3R1 of the circuit board 3 via the metal spring portions 4R1, 4R2, 4L1, and 4L2 of the metal plate 4, respectively. , 3R2 are in indirect contact with each other.

  In other words, the conductive rubber member 20d directly contacts the ground point 3L3 of the circuit board 3, and the conductive rubber member 20e directly contacts the ground point 3R2 of the circuit board 3, whereas the conductive rubber members 20a to 20c Through the mediation of the metal plate 4, they are in contact with the ground points 3L1, 3L2, and 3R1, 3R2 of the circuit board 3, respectively.

  As described above, the conductive rubber members 20 a to 20 e are in contact with the battery lid 1. For this reason, the battery lid 1 is grounded to the ground points 3L3 and 3R2 of the circuit board 3 through the conductive rubber member 20d and the conductive rubber member 20e, and through the conductive rubber members 20a to 20e and the metal plate 4. Thus, the grounding points 3L1, 3L2, and 3R1, 3R2 of the circuit board 3 are grounded.

  Thereby, the battery cover 1 can be reliably grounded to the ground points 3L1, 3L2, 3L3, 3R1, 3R2, and 3R3 of the circuit board 3 by the above-described five conductive rubber members 20a to 20e and the metal plate 4. . Further, the antenna unit for wireless communication is provided on the side opposite to the camera unit 12 of the circuit board 3 shown in FIG. 2, but the metal battery lid 1 is connected to each ground point 3L1, 3L2, of the circuit board 3. Since 3L3, 3R1, 3R2, and 3R3 can be reliably grounded, it is possible to prevent the metal battery lid 1 from adversely affecting antenna characteristics.

In addition, since the metal battery lid 1 and the ground points 3L1, 3L2, 3R1, 3R2 on the circuit board 3 are brought into contact with each other through the conductive rubber members 20a to 20c and the metal plate 4, the metal The position where the battery lid 1 and the metal plate 4 are brought into contact with each other and the position where the metal plate 4 and the ground points 3L1, 3L2, 3R1 and 3R2 on the circuit board 3 are brought into contact with each other can be set separately. As a result, the positions of the members 20a to 20c for making contact between the metal battery lid 1 and the metal plate 4 can be freely set by the designer, and the contact between the metal plate 4 and the ground point on the circuit board 3 can be made. The positions of the metal spring portions 4R1, 4R2 and 4L1, 4L2 to be designed can be freely set by the designer, which can contribute to the simplification of the design of the mobile phone.

[High-frequency noise suppression]
Next, in the case of the mobile phone of this embodiment, each ground point 3L1, 3L2, 3L3, 3R1, 3R2, 3R3 on the circuit board 3 is an antenna portion provided on the side of the circuit board 3 opposite to the camera unit 12 Are provided at positions substantially corresponding to the peak portion and the bottom portion of the signal waveform of the high-frequency noise signal generated from.

  Specifically, in the case where the casing of the mobile phone is formed of a conductive member such as a metal, when the grounding treatment of the casing formed of the conductive member is not performed, the antenna unit is connected as shown in FIG. The amplitude of the generated high frequency noise signal is increased, which adversely affects the antenna characteristics. For this reason, in the case of the mobile phone according to the present embodiment, each of the ground points 3L1, 3L2, 3L3, 3R1, 3R2, and 3R3 on the circuit board 3 has a high-frequency noise generated from the antenna unit as shown in FIG. They are provided at positions substantially corresponding to the peak portion and the bottom portion of the signal waveform of the signal.

As a result, as shown in FIG. 8C, the high-frequency noise signal generated from the antenna unit can be grounded at the timing of the peak portion and the bottom portion. For this reason, the amplitude of the high-frequency noise signal can be suppressed, and inconvenience that the high-frequency noise signal adversely affects the antenna characteristics of the antenna unit can be prevented.

[Effect of the embodiment]
As is clear from the above description, the mobile phone of this embodiment has the following effects compared to a mobile terminal device that uses a metal spring to make contact with a metal housing.

  1. When a metal spring is used, a certain effective length (= physical physical of the metal spring) is used in order to achieve stable contact between the metal housing and the ground point on the circuit board using the elasticity of the metal spring. Length) is required. As a result, the metal spring itself becomes large, causing a problem of requiring a large ground space. Moreover, in order to obtain stable antenna characteristics, a plurality of ground spaces are required. For this reason, a plurality of large grounding spaces are required, and there is a problem that hinders downsizing of the device.

  On the other hand, in the case of the cellular phone according to the embodiment, the metal battery lid 1 and the ground point on the circuit board 3, and the metal plate 4 that is in contact with the ground point on the circuit board 3 and the metal The battery lid 1 is in contact with each other through a conductive rubber member. Since the conductive rubber member has elasticity, the conductive rubber member is compressed by an appropriate pressure when the metal battery lid 1 is attached, and the ground point on the metal battery lid 1 and the circuit board 3 is compressed. The conductive rubber member comes into close contact with the metal plate 4, and the conductive rubber member comes into close contact with the metal plate 4 and the metal battery lid 1. Therefore, the metal battery lid 1 and the ground point on the circuit board 3, and the metal plate 4 in contact with the ground point on the circuit board 3 and the metal battery lid 1 are brought into stable contact with each other. And stable antenna characteristics can be obtained.

  Further, when a metal spring is used, the metal spring comes in contact with the battery lid at a “surface”, but the conductive rubber member is composed of a ground point on the metal battery lid 1 and the circuit board 3, and The metal plate 4 in contact with the ground point on the circuit board 3 and the metal battery lid 1 are in contact with each other at “dots”. For this reason, each grounding space can be made a very small grounding space, and even when a large number of grounding spaces are provided, the area on the mobile phone eroded by the grounding space can be reduced (= This makes it possible to reduce the total grounding space) and contribute to the downsizing and thinning of the equipment.

  2. When a metal spring is used, there is a problem that it becomes difficult to design the equipment because a plurality of large grounding spaces are required.

  On the other hand, in the case of the mobile phone of the embodiment, since the grounding space can be made extremely small by using the conductive rubber member, the position where the grounding space is provided can be made almost free. This can contribute to the simplification of the design of the mobile phone.

  Further, the metal battery lid 1 and the metal plate 4 are brought into contact with each other through a conductive rubber, and the metal plate 4 and a ground point on the circuit board 3 are connected to each other through a metal spring portion provided on the metal plate 4. It is designed to make contact. That is, the metal battery lid 1 and the ground point on the circuit board 3 are brought into contact with each other via the conductive rubber member and the metal plate 4.

  For this reason, the position where the metal battery lid 1 and the metal plate 4 are brought into contact with the position where the metal plate 4 and the ground point on the circuit board 3 are brought into contact with each other can be set separately. As a result, the position of the conductive rubber member that makes contact between the metal battery lid 1 and the metal plate 4 can be freely set by the designer, and contact between the metal plate 4 and the ground point on the circuit board 3 can be prevented. The position of the metal spring portion to be designed can be freely set by the designer, which can contribute to the simplification of the design of the mobile phone.

  3. Since the metal spring is formed by cutting out a sheet metal, the edge portion may be sharp. For this reason, when a metal spring is used, there is a problem that a troublesome processing such as cutting the edge portion roundly is necessary so as not to be injured even when the user touches it. Moreover, when a user touches and deform | transforms, a metal spring has the problem that it will become difficult to aim at the stable contact with a battery cover.

  On the other hand, the cellular phone according to this embodiment uses the elastic conductive rubber member to contact the metal battery lid 1 and the metal plate 4. The conductive rubber member has elasticity and does not have a sharp edge portion like a metal spring. For this reason, it is possible to prevent inconvenience that the user touches and is injured. Moreover, in order to prevent a user's injury, the troublesome process of cutting an edge part roundly etc. can be made unnecessary.

  Further, since the conductive rubber member is an elastic member, even when the user touches and deforms, the conductive rubber member immediately returns to the original shape and maintains stable contact with the battery lid 1 and the ground point on the circuit board 3. be able to.

  4). Since the metal spring is formed by cutting out a sheet metal, a hole is formed in a portion of the sheet metal where the metal spring is provided. For this reason, the water that has entered from the gap between the battery lid and the housing can easily enter the inside through the hole of the metal spring, and the circuit board or the like may be damaged. For this reason, when a metal spring is used, a special structure for waterproofing is required, which complicates the structure of the mobile phone and requires this special structure for waterproofing. There was a problem that caused trouble.

On the other hand, in the mobile phone according to the embodiment, the conductive rubber member is attached to the plastic frame portion 2 by inserting the conductive rubber member into the fitting hole 25 provided on the plastic frame portion 2. (See FIGS. 6A and 6B). The fitting portion 25 into which the conductive rubber member is inserted is closed by inserting the conductive rubber. In addition, the conductive rubber member is attached to the plastic frame portion 2 so that the flange portion 22 of each conductive rubber member covers the fitting hole 25. For this reason, even when water enters from the gap between the battery lid 1 and the plastic frame portion 2, the water does not enter the inside through the fitting hole 25 into which the conductive rubber member is inserted. Sufficient waterproofing can be achieved without taking a special structure. Therefore, by providing a special waterproof structure, it is possible to prevent the inconvenience of complicating the structure of the mobile phone and hindering downsizing.

[Modification]
In the above description of the embodiment, the present invention is applied to a mobile phone. However, the present invention is not limited to a PHS phone (PHS: Personal Handyphone System), a PDA device (PDA: Personal Digital Assistant), a portable game machine, You may apply to other portable terminal devices, such as a digital camera apparatus and a notebook-type personal computer apparatus. In either case, the same effect as described above can be obtained.

  Finally, the above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made according to the design and the like as long as they do not depart from the technical idea of the present invention. I add that there is something.

1 is a perspective view of a mobile phone according to an embodiment to which the present invention is applied. 1 is an exploded perspective view of a mobile phone according to an embodiment. It is a top view of the circuit board of the mobile phone used as an embodiment. It is a top view of the metal plate provided in the mobile phone of the embodiment. It is a figure which expands and shows the metal spring part of the metal plate provided in the mobile telephone of embodiment. It is a figure which expands and shows the electrically conductive rubber member provided in the mobile telephone of embodiment. It is a top view of the mobile telephone of embodiment in the state which mounted | wore with the metal plate. It is a figure for demonstrating the effect | action with respect to the installation position of the grounding point provided in the mobile telephone of embodiment, and a high frequency noise signal.

Explanation of symbols

  1 Battery cover on which conductive members are formed, 2 plastic frame, 3 circuit board, 3R1 to 3R3 installation point on the circuit board, 3L1 to 3L3 installation point on the circuit board, 4 metal plate, 4L1 to 4L2 provided on the metal plate Metal spring part, 4R1-4R2 metal spring part provided on the metal plate, 11 screw hole in the circuit board, 12 camera unit, 13 speaker part, 14-16 connection end part of the metal plate in contact with the conductive rubber member, DESCRIPTION OF SYMBOLS 17 Battery connection terminal of a circuit board, 18 Battery storage part, 20a-20e Conductive rubber member, 21 Insertion support | pillar part of a conductive rubber member, 22 Flange part of a conductive rubber member, 23 Contact pillar part of a conductive rubber member, 24 Conductive rubber Contact pillar portion of member, 25 Insertion hole for inserting conductive rubber member provided on circuit board

Claims (5)

A housing formed of a conductive member;
A circuit board housed in the housing;
A plurality of ground points provided at predetermined locations on the circuit board;
An intermediary conductive member having a contact portion that contacts a ground point on the circuit board;
A plurality of conductive rubber members provided so that one end portion contacts the housing and the other end portion contacts the intermediate conductive member;
A portable terminal device characterized in that a casing formed of the conductive member is grounded to a ground point on the circuit board via the contact portion of the conductive rubber member and the intermediate conductive member. As the conductive rubber member, in addition to the conductive rubber member provided so as to be in contact with the intermediate conductive member, one end portion is in contact with the casing, and the other end portion is a grounding point of the circuit board housed in the casing A portable terminal device comprising a plurality of conductive rubber members provided so as to be in contact with the mobile phone. The portable terminal device according to claim 1 or 2, wherein
Having an antenna for wireless communication,
The portable terminal device, wherein the ground points on the circuit board are respectively provided at positions substantially corresponding to a peak portion and a bottom portion of a signal waveform of a high-frequency noise signal generated from the antenna unit. It is a portable terminal device given in any 1 paragraph among Claims 1-3,
The case is a metal case formed of a metal member,
The intermediary conductive member is a metal plate formed of a metal plate, and has a metal spring in the form of a leaf spring by cutting out and bending the metal plate as the contact portion. Terminal device. A method for grounding a mobile terminal device in which a circuit board having a plurality of grounding points is housed in a housing formed of a conductive member,
The conductive rubber member is formed of the conductive member by bringing one end of the conductive rubber member into contact with the housing and the other end of the conductive rubber member into contact with an intermediate conductive member having a plurality of contact portions that are in contact with the ground points of the circuit board. A grounding method for a portable terminal device, wherein the casing is grounded to a grounding point on the circuit board via the contact portion of the conductive rubber member and the intermediate conductive member.

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