Portable electronic apparatus electrically shielding hinge portion

Abstract: A portable computer includes a main body (1) and a removable display unit (6). The main body has a receiv­ ing member (9) rotatably supported on the main body by a hinge shaft (8) which is fixed to the main body and electrically connected to a shielding layer (3) of the main body for electromagnetically shielding the main body. A conductive layer (11) is formed on the receiv­ ing member and electrically connected to the hinge shaft by means of a elastic conducting piece (15). The dis­ play unit has a connecting portion (18) removably fitted to the receiving member and having a conductive portion electrically connected to a shielding layer (20) of the display unit for electromagnetically shielding the dis­ play unit. An elastic contact piece (16) is fixed to the conductive portion of the receiving member, and a contact portion (21) is formed on the conductive por­ tion of the connecting portion and elastically contact the contact piece to electrically connect the conductive portions to each other.

Description: The present invention relates to an electronic apparatus as defined in the preamble of claim 1 such as a portable lap-top type personal computer and a portable word processor. A portable electronic apparatus, such as a lap-top type personal computer, generally comprises a keyboard mounted on the upper front portion of a main body and a flat display unit pivotally connected between the keyboard and the rear portion of the main body. When the display unit is closed, the keyboard is covered with the display unit. There has recently been developed a lap-top computer in which the display unit is removable from the main body, as shown in the United States Patent 4,749,364. In general, a personal computer has a main circuit board housed in the main body and a shielding portion, such as a shielding layer formed on the inner surface of the main body, for shielding noise generated by the main circuit board and external noise giving an adverse effect on the main circuit board. Since the display unit houses a drive circuit therein, it is preferred that the display unit like the main body be shielded from noise. In a computer having a removable display unit, if, however, the shielding layer is formed on the display unit, the structure, for removably mounting the display unit on the main body, hinders the shielding layer from being electrically connected to the ground circuit in the main body. With the most conventional lap-top type personal computers each having a removable display unit, therefore, the display units are not grounded, exhibiting a poor shielding characteristic. The prior art portable computer described in US-A-4,749,364 has the features defined in the preamble portion of claim 1. The hinge shaft of the display of this apparatus is attached to the main body of the apparatus with its one end and fixed or screwed with its other end to sockets serving as receiving members. The display unit is insertable with plugs into the sockets. The problem of electromagnetic shielding is however not adressed in this reference. A shielded casing is described in EP-0 269 126 A1 whereby this casing has no parts to be shielded which are rotatably connected to the main body of the casing. It is the object of the present invention to improve an electronic apparatus as defined in the preamble of claim 1 so that the removable display unit can be fully and reliably shielded by a simple construction. In order to attain this object, an electronic apparatus in accordance with the present invention comprises a main body having a main body shielding portion for electromagnetically shielding an interior of the main body, and a hinge shaft fixed to the main body; a receiving member supported by the hinge shaft to be rotatable with respect to the main body, said receiving member having an externally open mounting portion, and an electrically shielding portion provided on an inner face of the mounting portion; and a display unit having a connecting portion removably fittable to the mounting portion and rotatable together with the receiving member, and a display unit shielding portion for electromagnetically shielding an interior of the display unit; wherein said hinge shaft is electrically conductive and has one end portion which is fixed to the main body and electrically connected to the main body shielding portion, and a free end portion projecting into the mounting portion; said connecting portion has an electrically shielding portion electrically connected to the display unit shielding portion, and an engagement portion for engaging with the free end portion of the hinge shaft when the connecting portion is fitted to the mounting portion; and that there is provided first conducting means for electrically connecting the shielding portion of the receiving member with the shielding portion of the connecting portion when the connecting portion is fitted to the mounting portion of the receiving member; and second conducting means provided in the mounting portion for electrically connecting the free end portion of the hinge shaft and the shielding portion of the receiving member, wherein said receiving member has a pair of opposed lateral walls defining the mounting portion, said shielding portion of the receiving member has an electrically conductive layer formed on inner surfaces of said lateral walls, and said second conducting means comprises a conductive curved plate spring arranged in the mounting portion and having two ends elastically contacting said inner surfaces of the lateral walls, and an intermediate portion elastically contacting the free end portion of the hinge shaft. Preferred embodiments of the electronic apparatus are defined in the subclaims. With the electronic apparatus of the present invention having the above-mentioned construction, when the display unit is mounted on the main body by inserting the connecting portion in the mounting portion of the receiving member, the connecting portion, which is electrically connected to the shielding portion of the display unit, can be electrically connected to the shielding portion of the main body through the first conducting means, the conductive shielding portion of the connecting portion, the second conducting means, and the hinge shaft. This structure allows the shielding portions of both the display unit and the main body to be properly grounded and permits the display unit and the main body to be fully shielded. The grounding operation of the shielding portion of the display unit is carried out in a simple way because it uses the same mounting operation of the display unit on the main body. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Figs. 1 to 7 show a lap-top type portable computer according to an embodiment of the present invention, in which: Fig. 1 is a perspective view of the whole computer in a state wherein a display unit is fitted to a main body of the computer; Fig. 2 is a perspective view of the computer in a state wherein the display unit is removed; Fig. 3 is a cross-sectional view of the conducting structure of the shielding portions, in a state wherein the display unit is fitted to the main body; Fig. 4 is a cross-sectional view taken along line IV-IV of Fig. 3; Fig. 5 is a cross-sectional view taken along line V-V of Fig. 3; Fig. 6 is a cross-sectional view of an essential part of the computer, in which the display unit is removed; and Fig. 7 is a cross-sectional view taken along line VI-VI of Fig. 6. The present invention will now be explained by way of an embodiment with reference to Figs. 1 to 7. As shown in Figs. 1 to 3, a lap-top type portable computer to which the present invention is applied has a flat box shaped main body 1 which has a thin front portion 1a and a thick rear portion 1b. A keyboard 2 is provided on the front portion 1a of the main body 1. On the inner face (over the whole area of the inner face, for example) of the main body 1 is formed a plated layer 3 (see Fig. 3) acting as an electrically conductive layer which is electrically connected to the ground circuit of a main circuit board, not shown. The plated layer 3 constitutes a shielding portion of the main body 1 for shielding the interior of the main body from electromagnetic waves. In the front central part of the upper portion 4 of the rear portion 1b is formed a recess 5 opened upward and forward. A flat display unit 6 is mounted in the recess 5 so as to be swingable back and forth and so as to be removable from the main body 1. The mounting structure of the display unit 6 on the main body 1 is shown in Figs. 2 to 7. Specifically, adjacent to the lateral walls defining the recess 5 in the rear portion 1b are provided a pair of hinges such as hinge devices 7 which are generally so called as a shaft rocking device. Each hinge device 7 has a cylinder 8a acting as a mounted portion, a hinge shaft 8 approximately half portion of which is rotatably inserted in the cylinder 8a and acts as a supporting portion, and a densely wound coil spring (not shown) for interconnecting the cylinder 8a with the hinge shaft 8. The hinge device 7 is fixed by screws to the inner surface of the upper portion 4 so that the distal end portion of the hinge shaft 8 projects into the recess 5 passing through the lateral wall of the main body 1, which defines the recess. Each component of the hinge device 7 is made of an electrically conductive metal and the overall hinge device 7 is electrically connected to the plated layer 3 of the main body 1. A receiving member 9 is arranged in the recess 5 and is swingably supported by the distal end portions of the hinge shafts 8 projecting inwardly from the respective side walls of the recess 5. Specifically, the receiving member 9 has an elongated box-like shape in correspondence with the shape of the recess 5. The member 9 has a bottom with an arcuated cross section and opens at the top. The inner surface of the receiving member 9 defines a mounting portion 9a in which a connecting portion of the display unit 6 as described later is fitted. A plated layer 11 serving as an electrically conductive portion is formed on the inner surface (the whole area of the inner surface, for example) of the receiving member 9. The side walls of the receiving member 9 are swingably supported on the respective end portions of the hinge shafts 8 by means of bearings 10. In the both lateral end portions of the receiving member 9 are provided cover plates 12 so as to cover the bearings 10. The distal end of each hinge shaft 8 is provided with a plate-like engaging portion 8b (see Fig. 2) which projects into the mounting portion 9a passing through the corresponding cover plate 12. A connector 14 is located at the central portion in the mounting portion 9a of the receiving member 9 and is connected to the main circuit board in the main body 1 by means of a flexible wire 14a. As shown in Figs. 4 and 7, a belt-like contact piece 16 (first conducting means) having an arcuated movable portion 16a is attached to the central part of the inner face of each of the front and rear walls of the receiving member 9 so that the movable portion 16a extends in the mounting portion 9a. Each contact piece 16 is electrically connected to the plated layer 11 of the receiving member 9. As shown in Figs. 3 and 5, each cover plate 12 is spaced apart by a predetermined distance δ from the corresponding side wall of the receiving member 9. An arcuated base member 13 is arranged right under the hinge shaft 8 in a space defined by each cover plate 12 and the corresponding side wall. At least the arcuated face of the base member 13, which faces the hinge shaft 8, is plated. In other words, at least the arcuated face of the base member 13 constitutes an electrically conductive portion. An elastic belt-like conductive piece 15 (second conducting means) formed of a plate spring is sandwiched between the arcuated face of the base member 13 and the hinge shaft 8 disposed thereabove. The conductive piece 15 has a length larger than the inner dimension of the receiving member 9, that is, the distance between the front and rear walls of the receiving member, and is curved at a radius of curvature larger than that of the arcuated face of the base member 13. As elastically deformed, the conductive piece 15 contacts at its central portion with the hinge shaft 8 and at its both end with the plated layer 11 of the receiving member 9. Thus, the hinge shaft 8 is electrically connected to the plated layer 11 of the receiving member 9 by means of the conductive piece 15. The display unit 6 comprises a flat box like cover 6a, a flat panel display 17 such as a liquid crystal display housed in the cover 6a, and an electronic circuit board (not shown) for driving the flat panel display 17. The inner face (the whole area of the inner face, for example) of the cover 6a is coated with a plated layer 20 as an electrically conductive layer which constitutes a shielding portion of the display unit, for shielding the interior of the cover 6a. From the lower end of the cover 6a projects a box-like connecting portion 18 which is adapted to be fitted in the mounting portion 9a of the receiving member 9. On the central part of the connecting portion 18 is arranged an insert terminal 19 which is connected to the electronic circuit board of the display unit 6. When the connecting portion 18 is fitted in the receiving member 9, the terminal 19 is connected to the connector 14 in the main body 1. Plated layers 21a are formed on that outer surfaces of the lateral walls of the connecting portion 18 which face the corresponding contact pieces 16, and are electrically connected to the plated layer 20 by means of a reinforcement frame 19 fitted in the connecting portion. A contact portion 21 formed of a depression extending in the direction of the extension of the connecting portion 18 is formed in the outer surface of each lateral wall on which the plated layer 21a is formed. When the connecting portion 18 is fitted in the mounting portion 9a of the receiving member 9, the contact portions 21 contact the movable portions 16a of the contact pieces 16, respectively. The connection between them allows the shielding portion of the display unit 6 (that is, the plated layer 20) to be grounded to the main body 1. Notches 22 are formed in the extended ends of the connecting portion 18 and the reinforcement frame 19. When the connecting portion 18 is fitted in the mounting portion 9a of the receiving member 9, the notches 22 engage the engaging portions 8b on the distal ends of the hinge shafts 8 projecting in the mounting portion 9a. Accordingly, only when the receiving member 9 and the display unit 6 are rotated while the connecting portion 18 is fitted in the receiving member 9, the hinge shafts 8 are rotated to perform the shaft rocking function of the hinge devices 7. By connecting the connecting portion 18 to and disconnecting it from the receiving member 9, the display unit 6 is mounted on and removed from the main body 1. After the connecting portion 18 is fitted to the receiving member 9, they are secured to each other by screws from outside the main body 1. In Fig. 2, reference numeral 23 represents a decorative plate for covering the threaded holes which are otherwise exposed externally of the receiving member 9. According to the computer constructed above, by fitting the connecting portion 18 of the display unit 6 in the mounting portion 9a of the receiving member 9 after the receiving member 9 is set substantially vertically, as shown in Fig. 2, the display unit 6 can be mounted on the main body 1. At the same time, the shielding portion of the display unit 6 is electrically connected to the main body 1 through the connecting portion 18, thus being grounded. Specifically, as shown in Figs. 6 and 7, as the connecting portion 18 is inserted in the receiving member 9, the contact portions 21 of the connecting portion 18 slidably contact the movable portions 16a of the contact pieces 16 fixed to the receiving member 9. Further, while keeping the sliding contact between the contact portions 21 and the movable portions 16a, the insert terminal 19 in the connecting portion 18 is connected to the connector 14 in the receiving member 9, and the engaging portions 23 of the hinge shafts 8 engage the respective notches 22 formed in the lower portion of the connecting portion 18, as shown in Figs. 3 and 4. The hinge shaft 8 of each hinge device 7 is electrically connected to the plated layer 11 on the inner face of the receiving member 9 through the conductive piece 15. Therefore, the connecting portion 18 electrically connected to the plated layer 20 of the display unit 6 is electrically connected to the plated layer 3 of the main body 1 through the contact portions 21, the contact pieces 16, the plated layer 3 on the inner face of the receiving member 9, the conductive piece 15, and the hinge shafts 8 of the hinge units 7. On the contrary, the display unit 6 can be removed from the main body 1 by detaching the connecting portion 18 from the receiving member 9. Thereupon, the electrical connection between the display unit 6 and the main body 1 is interrupted. According to the personal computer constructed as described above, the electrical connection between the hinge devices 7 and the receiving member 9 is attained by the elastic conductive pieces 15 disposed therebetween. Even if, therefore, there is a substantive assembling error between the hinge devices 7 and the receiving member 9, the elastic deformation of the conductive pieces 15 ensures that these pieces are in contact with the hinge shafts 8 and the plated layer 11 of the receiving member 9, thereby electrically connecting the hinge shafts and the plated layer to each other securely. Further, the electrical connection between the connecting portion 18 and the receiving member 9, between which the display unit 6 can be separated from the main body 1, is attained by the contact pieces 16 with the movable portions 16a and the contact portions 21. In this respect, even if there is a substantive manufacturing error in the arrangement of the connecting portion 18 and the receiving member 9, the action of the movable pieces 16a ensures the electrical connection between the connecting portion 18 and the receiving member 9. These arrangements enable the computer having a removable display unit 6 to cause the shielding portion of the display unit 6 (namely, the plated layer 20) to be securely connected to the ground portion of the main body 1, with the result that the display unit 6 is fully shielded from the electromagnetic waves. It is a notable feature that the grounding operation is automatically carried out in interlock with the mounting operation of the display unit 6 on the main body 1. In the above, the present invention is applied to a personal computer. However, the present invention is not limited thereto, but may be applied to other portable electronic apparatuses such as word processors. Further, the contact pieces 16 may be fixed to the connecting portion 18 of the display unit 6 and the contact portions 21 may be formed on the inner face of the receiving member 9.

Claims: An electronic apparatus comprising: a main body (1) having a hinge shaft (8) fixed to the main body; a receiving member (9) supported by the hinge shaft (8) to be rotatable with respect to the main body (1), said receiving member (9) having an externally open mounting portion (9a); and a display unit (6) having a connecting portion (18) removably fittable to the mounting portion (9a) and rotatable together with the receiving member (9); characterized in that said main body (1) has a main body shielding portion (3) for electromagnetically shielding an interior of the main body; said receiving member (9) has an electrically shielding portion (11) provided on an inner face of the mounting portion (9a) ; said display unit (6) has a display unit shielding portion (20) for electromagnetically shielding an interior of the display unit; said hinge shaft (8) is electrically conductive and has one end portion which is fixed to the main body (1) and electrically connected to the main body shielding portion (3), and a free end portion projecting into the mounting portion (9a) ; said connecting portion (18) has an electrically shielding portion (21a) electrically connected to the display unit shielding portion (20), and an engagement portion (22) for engaging with the free end portion of the hinge shaft (8) when the connecting portion (18) is fitted to the mounting portion (9a); and that there is provided first conducting means (16) for electrically connecting the shielding portion (11) of the receiving member (9) with the shielding portion (21a) of the connecting portion (18) when the connecting portion is fitted to the mounting portion (9a) of the receiving member (9) ; and second conducting means (15) provided in the mounting portion (9a) for electrically connecting the free end portion of the hinge shaft (8) and the shielding portion (11) of the receiving member (9), wherein said receiving member (9) has a pair of opposed lateral walls defining the mounting portion (9a), said shielding portion (11) of the receiving member has an electrically conductive layer formed on inner surfaces of said lateral walls, and said second conducting means comprises a conductive curved plate spring (15) arranged in the mounting portion (9a) and having two ends elastically contacting said inner surfaces of the lateral walls, and an intermediate portion elastically contacting the free end portion of the hinge shaft. An apparatus according to claim 1, characterized in that said second conducting means has a base member (13) fixedly arranged in the mounting portion (9a) so as to face the free end portion of the hinge shaft (8) with a predetermined space, and said conductive curved plate spring (15) is interposed between the hinge shaft and the base member. An apparatus according to claim 2, characterized in that said base member (13) has an arcuated supporting face opposed to the hinge shaft (8), and said conductive curved plate spring (15) is curved at a radius of curvature larger than that of the supporting face. An apparatus according to any one of claims 1 to 3, characterized in that said first conducting means includes an elastic contact piece (16) attached to either one of said shielding portions (21a, 11) of the connecting portion (18) and the receiving member (9), and a contact portion (21) formed on the other one of said shielding portions and contacting the elastic curved plate spring (15). An apparatus according to claim 4, characterized in that said receiving member (9) has lateral walls defining said mounting portion (9a) and an electrically conductive layer formed on an inner face of each of said lateral walls and constituting said electrically shielding portion (11) of the receiving member, and said elastic contact piece (16) is fixed onto the electrically shielding layer of the receiving member and has an elastically deformable moving portion (16a) which projects in the mounting portion. An apparatus according to claim 5, characterized in that said electrically shielding portion (21a) of the connecting portion (18) has an electrically conductive layer formed on an outer surface of the connecting portion, and said contact portion (21) has a depression formed in the outer surface of the connecting portion and elastically engaging the moving portion (16a) of the elastic contact piece (16). An apparatus according to any one of claims 1 to 6, characterized in that said display unit (6) comprises a flat display (17), a cover (6a) enclosing the flat display, and an electrically conductive layer (20) formed over the substantially whole area of an inner face of the cover and constituting the shielding portion of the display unit, and said connecting portion (18) projects from the cover. An apparatus according to any one of claims 1 to 7, characterized in that said shielding portion of the main body (1) has an electrically conductive layer (3) formed over the substantially whole area of an inner face of the main body.

Inventors: SATOU YOUJI, SATOU, YOUJI, SATOU, YOUJI, C/O INTELLECTUAL PROPERTY DIVISION
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 1990
Main classification: G06F1
IPC codes: G06F1