Patent Publication Number: US-8115691-B2

Title: Electronic apparatus and antenna unit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2008-305125, filed Nov. 28, 2008, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     One embodiment of the invention relates to an antenna unit provided with a plurality of antennas, and an electronic apparatus. 
     2. Description of the Related Art 
     In Jpn. Pat. Appln. KOKAI Publication No. 2003-152445, a composite antenna provided with first and second antennas is disclosed. The first antenna is a circular polarized loop antenna for GPS, and is provided on a dielectric board. The second antenna is a square patch antenna for ETC, and is provided substantially concentric with the first antenna. 
     In recent years, an electromagnetic induction type flat-panel antenna for proximity communication represented by, for example, Felice (trade name) or the like is provided. Furthermore, at present, an electric field induction type solid antenna for proximity communication, such as TransferJet (trade name) is being developed. 
     The present inventor considers mounting of a plurality of different antennas for proximity communication on an electronic apparatus. The present inventor further considers that if communication can be performed by making communication modules which are communication partners close to or in contact with one part of the electronic apparatus, the convenience for the user is enhanced. 
     However, when two antennas for proximity communication are arranged in layers above and below, the distance between the antenna contained in the housing on the inner side of the housing and the communication module becomes large, and there is the possibility of the antenna performance being lowered. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A general architecture that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. 
         FIG. 1  is an exemplary perspective view of a portable computer according to a first embodiment of the present invention; 
         FIG. 2  is an exemplary perspective view of an antenna unit according to the first embodiment of the present invention; 
         FIG. 3  is an exemplary perspective view showing the antenna unit shown in  FIG. 2  in a partly disassembled manner; 
         FIG. 4  is an exemplary cross-sectional view showing the antenna unit shown  FIG. 2 ; 
         FIG. 5  is an exemplary cross-sectional view showing the antenna unit shown in  FIG. 2  in a partly disassembled manner; 
         FIG. 6  is an exemplary perspective view of an antenna unit according to a second embodiment of the present invention; 
         FIG. 7  is an exemplary perspective view showing the antenna unit shown in  FIG. 6  in a partly disassembled manner; 
         FIG. 8  is an exemplary cross-sectional view showing the antenna unit shown  FIG. 6 ; and 
         FIG. 9  is an exemplary cross-sectional view showing the antenna unit shown in  FIG. 6  in a partly disassembled manner. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, an electronic apparatus comprises: (i) a housing; (ii) a first board contained in the housing; (iii) a second board contained in the housing on the inner side of the first board; (iv) a first antenna part comprising a loop antenna provided on the first board, and the first antenna part being configured to communicate with a communication module opposed to the loop antenna; and (v) a second antenna part comprising an element part provided in an area surrounded by the loop antenna, and positioned in the same plane as the loop antenna, and a ground part provided on the second board, and the second antenna part being configured to communicate with a communication module opposed to the element part. 
     In general, according to one embodiment of the invention, an antenna unit comprising: (i) a first board; (ii) a second board arranged parallel with the first board; (iii) a first antenna part comprising a loop antenna provided on the first board, and the first antenna part being configured to communicate with a communication module opposed to the loop antenna; and (iv) a second antenna part comprising an element part provided in an area surrounded by the loop antenna, and positioned in the same plane as the loop antenna, and a ground part provided on the second board, and the second antenna part being configured to communicate with a communication module opposed to the element part. 
     An embodiment of the present invention will be described below on the basis of a drawing of a portable computer to which the present invention is applied. 
     First Embodiment 
       FIGS. 1 to 5  disclose a portable computer  1  as an electronic apparatus, and an antenna unit  2  according to a first embodiment of the present invention. As shown in  FIG. 1 , the portable computer  1  comprises a main unit  3  which is an apparatus main body, and a display unit  4 . 
     The main unit  3  has a main housing  5  formed into a flat box-like shape. The main housing  5  is an example of the housing mentioned in the present invention. The main housing  5  comprises an upper wall  6 , peripheral wall  7 , and lower wall  8 . The upper wall  6  spreads in the substantial horizontal direction. The peripheral wall  7  extends downwardly from the edge part (for example, the edge part of the whole circumference) of the upper wall  6 . The lower wall  8  spreads substantially horizontally (i.e., in substantial parallel with the upper wall  6 ) to connect the lower end parts of the peripheral wall  7  to each other. 
     The main housing  5  comprises a housing base  11  (i.e., lower cover), and housing cover  12  (i.e., upper cover). The housing base  11  comprises the lower wall  8  and part of the peripheral wall  7 . The housing cover  12  comprises the upper wall  6 , and part of the peripheral wall  7 . The housing cover  12  is combined with the housing base  11  from above. 
     As shown in  FIG. 1 , the display unit  4  is supported on the rear end part  5   b  of the main housing  5  by way of, for example, a pair of hinge parts  13   a  and  13   b . The display unit  4  is rotatable between a closed position, in which the unit  4  is laid down to cover the upper wall  6  of the main housing  5  from above, and an opened position, in which the unit  4  is raised on the upper wall  6 . 
     The main housing  5  comprises a front end part  5   a  on the opposite side of the display unit  4  of the main housing  5 . The peripheral wall  7  described above comprises a front wall  7   a , a back wall  7   b , and a pair of right and left side walls  7   c  and  7   d . The front wall  7   a  is positioned at the front end part  5   a  of the main housing  5 . The back wall  7   b  is positioned at the rear end part  5   b  (i.e., the end part supporting the display unit  4 ) of the main housing  5 . The left side wall  7   c  and right side wall  7   d  extend at parts between the edge part of the front wall  7   a  and the edge part of the back wall  7   b.    
     As shown in  FIG. 1 , the upper wall  6  comprises a keyboard mounting part  16  on which a keyboard  15  is placed, and supports the keyboard  15 . The upper wall  6  comprises a palm rest part  17  on the near side (i.e., on the front wall  7   a  side of the keyboard mounting part  16 ) of the keyboard mounting part  16 . 
     As shown in  FIG. 1 , the display unit  4  comprises a display housing  18 , and a display panel  19  contained in the display housing  18 . The display panel  19  comprises a display screen  19   a . The display screen  19   a  is exposed to the outside of the display housing  18  through an opening part  18   a  in a front wall of the display housing  18 . 
     As shown in  FIG. 1 , the portable computer  1  comprises an antenna unit  2  mounted in the main housing  5 . The antenna unit  2  is provided at a part, for example, under the palm rest part  17 , and is arranged along an inner surface (inside surface) of the upper wall  6 . 
     As shown in  FIGS. 2 to 5 , the antenna unit  2  comprises first and second boards  21  and  22 , first and second antenna parts  23  and  24 , and spacers  25 . 
     As shown in  FIG. 4 , the first board  21  is contained in the main housing  5 . The first board  21  is a so-called loop antenna board (electromagnetic induction antenna board). The first board  21  is opposed to the inner surface  5   i  (e.g., the inner surface of the upper wall  6 ) of the main housing  5 . The first board  21  is positioned closer to the outside of the main housing  5  than the second board  22 . The first board  21  comprises a first board surface  21   a  opposed to the inner surface  5   i  of the main housing  5 , and a second board surface  21   b  opposed to the second board  22 . 
     As shown in  FIGS. 2 to 5 , the first antenna part  23  comprises a loop antenna  31 . The loop antenna  31  is provided on the first board  21 . More specifically, the loop antenna  31  is formed on the first board surface  21   a  of the first board  21 , and is opposed to the inner surface  5   i  of the main housing  5 . The loop antenna  31  is formed into, for example, an annular shape surrounding a central part of the first board  21 . 
     The first antenna part  23  the loop antenna  31 ) is an antenna for proximity communication. The first antenna part  23  is, for example, an electromagnetic induction type flat-panel antenna. An example of the first antenna part  23  is an antenna for Felica. As shown in  FIG. 4 , the first antenna part  23  is configured to communicate with a communication module M opposed to the loop antenna  31  from outside the main housing  5 . The communication-enabled distance of the first antenna part  23  is, for example, 3 cm or less. 
     As shown in  FIGS. 3 and 5 , the first antenna part  23  comprises a transmission and reception circuit part  32 . The transmission and reception circuit part  32  is electrically connected to the loop antenna  31  through a first antenna cable  33  and a connector or the like (not shown). The transmission and reception circuit part  32  is mounted on, for example, the second board  22 . It should be noted that the transmission and reception circuit part  32  may be provided outside the first and second boards  21  and  22 . 
     As shown in  FIG. 4 , the second board  22  is contained in the main housing  5  on the inner side of the first board  21 . The second board  22  is arranged in parallel with the first board  21  with a gap C held between the second board  22  and the first board  21 . The second board  22  is a so-called electric field induction antenna board. The second board  22  comprises a first board surface  22   a  opposed to the first board  21 , and a second board surface  22   b  facing the inside of the main housing  5 . 
     As shown in  FIGS. 3 and 5 , the second antenna part  24  comprises an element part  41 , ground part  42 , resonance stub  43 , and connection part  45 . The ground part  42  is provided on the second board surface  22   b  of the second board  22 . An example of the ground part  42  is a ground plane arranged on the second board  22 . The resonance stub  43  is provided on the first board surface  22   a  of the second board  22 . The resonance stub  43  has electrical conductivity. 
     The element part  41  is a so-called electrode (i.e., coupling electrode), and a gap is held between the element part  41  and the second board  22  (i.e., resonance stub  43 ). The element part  41  is opposed to the resonance stub  43 . The connection part  45  (i.e., a so-called electrode-resonance stub connection leg) is erected between the resonance stub  43  and element part  41 . The connection part  45  is interposed between the resonance stub  43  and element part  41 , whereby the element part  41  is supported on the second board  22 . The connection part  45  has electrical conductivity, and electrically connects the element part  41  to the resonance stub  43 . 
     The second antenna part  24  is an antenna for proximity communication. The second antenna part  24  is, for example, an electric field induction type solid antenna. An example of the second antenna part  24  is an antenna (i.e., a so-called coupler) for TransferJet. As shown in  FIG. 4 , the second antenna part  24  is configured to communicate with a communication module M opposed to the element part  41  from outside the main housing  5 . The communication-enabled distance of the second antenna part  24  is, for example, 3 cm or less. The second antenna part  24  is electrically connected to a transmission and reception circuit (not shown) through a second antenna cable  46 . 
     As shown in  FIGS. 3 and 5 , the first board  21  comprises an opening part  51  in an area (e.g., a central part of the first board  21 ) surrounded by the loop antenna  31 . That is, the opening part  51  is provided in an area opposed to the element part  41  of the second antenna part  24 . The opening part  51  is formed one size larger than the outer shape of the element part  41 . 
     As shown in  FIGS. 2 and 4 , the second board  22  is laid on the first board  21  with a gap C held between them. The element part  41  is inserted in the opening part  51  of the first board  21 , and is contained in the opening part  51 . As a result of this, the element part  41  is provided in the area surrounded by the loop antenna  31 , and is positioned flush with the loop antenna  31 . That is, the flat-panel antenna for proximity communication using the electromagnetic induction system, and the solid antenna for proximity communication using the electric field induction system are mounted on a part at the same position and in the same plane. 
     As shown in  FIG. 4 , spacers  25  are interposed between the first and second boards  21  and  22 . A height of the first board  21  (i.e., the gap C between the first and second boards  21  and  22 ) above the second board  22  is adjusted by means of the spacers  25 . As the spacers  25 , those having a height that position the loop antenna  31  and the element part  41  in the same plane are employed. 
     Next, the function of the portable computer  1  will be described below. 
     By making the communication module M, which the partner of communication in the electromagnetic induction system, close to or in contact with the palm rest part  17  at which the antenna unit  2  is arranged, the user can perform communication using the electromagnetic induction system. Further, by making the communication module M, which is the partner of communication in the electric field induction system, close to or in contact with the palm rest part  17  at which the antenna unit  2  is arranged, the user can perform communication using the electric field induction system. 
     That is, by making the communication module M, which is the partner of communication in the electromagnetic induction system or the communication module M which is the partner of communication in the electric field induction system close to or in contact with the same part of the portable computer  1 , the user can perform proximity communication using the respective communication systems. 
     Further, the antenna part (e.g., an antenna part for Felica) based on the electromagnetic induction system and the antenna part (e.g., an antenna part for TransferJet) based on the electric field induction system differ from each other in the communication system and communication frequency. Accordingly, by making an electronic apparatus in which both the communication module M which is the partner of communication in the electromagnetic induction system and the communication module M which is the partner of communication in the electric field induction system are incorporated close to a part of the portable computer  1 , the user can simultaneously perform proximity communication in the two communication systems. 
     According to the antenna unit  2  configured as described above, the antenna performance becomes hardly lowered. That is, if it is temporarily assumed that two antennas for proximity communication are arranged in layers above and below, the distance between the antenna contained in the housing  5  on the inner side of the housing  5  and the communication module M which is to communicate with the antenna becomes large, and there is the possibility of the antenna performance being lowered. Furthermore, between the antenna contained in the housing  5  on the inner side of the housing  5  and the communication module M which is to communicate with the antenna, the other antenna is present. When an unnecessary substance is present between an antenna and a communication module, there is the possibility of the antenna performance being lowered. 
     On the other hand, in the antenna unit  2  according to this embodiment, the element part  41  of the second antenna part  24  is provided in the area of the first antenna part  23  surrounded by the loop antenna  31 , and thus the loop antenna  31  and the element part  41  are arranged at the same part. As a result of this, communication is enabled by making the communication module M which is the communication partner in each of the communication systems close to or in contact with the same part of the portable computer  1 , and the convenience of the user is improved. 
     Further, the loop antenna  31  of the first antenna part  23  and the element part  41  of the second antenna part  24  are positioned in the same plane, and hence it is possible to arrange both the loop antenna  31  and the element part  41  at a position in the main housing  5  relatively close to the outside of the main housing  5 . Accordingly, the antenna performance of each of the first and second antenna parts  23  and  24  is hardly lowered. 
     Furthermore, according to the structure of this embodiment, it is possible to arrange two antenna parts different from each other in type at the same position, and in the same plane while maintaining the size of the first board  21  (loop antenna board) as it is, and hence it becomes possible to largely reduce the antenna mounting area. 
     When the second antenna part  24  comprises the resonance stub  43  provided on the second board  22 , and the connection part  45  which is erected between the resonance stub  43  and element part  41 , and electrically connects the element part  41  to the resonance stub  43 , it is possible to obtain the above-mentioned effect by the antenna unit  2  provided with, for example, the antenna part for TransferJet. 
     When the first board  21  comprises the opening part  51  in the area surrounded by the loop antenna  31 , and the element part  41  is inserted in the opening part  51  to be positioned on the same plane as the loop antenna  31 , it is possible to realize the above-mentioned structure by a relatively simple structure. 
     When the transmission and reception circuit part  32  the first antenna part  23  is mounted on the second board  22 , it is possible to mount the transmission and reception circuit part  32  while avoiding the opening part  51  (i.e., the element part  41 ) without increasing the size (i.e., the size of the loop antenna  31 ) of the first board  21 . This contributes to reduction in the size of the antenna unit  2 . When the spacers  25  interposed between the first and second boards  21  and  22  are provided, it is possible to position the loop antenna  31  and element part  41  in the same plane by a relatively simple structure. 
     Second Embodiment 
     Next, a portable computer  1  and an antenna unit  2  as an electronic apparatus according to a second embodiment of the present invention will be described below with reference to  FIGS. 6 to 9 . It should be noted that the configuration comprising a function identical with or similar to that of the first embodiment is denoted by the identical reference symbol, and a description thereof will be omitted. Further, the configurations of the portable computer  1  and the antenna unit  2  other than those described below are identical with the first embodiment. 
     As shown in  FIGS. 7 and 9 , a first board  21  does not comprise an opening part  51 . An element part  41  is provided on the first board  21 . More specifically, as shown in  FIG. 9 , the element part  41  is formed on a first board surface  21   a  of the first board  21 . The element part  41  is provided in an area (e.g., a central part of the first board  21 ) surrounded by a loop antenna  31 . 
     As shown in  FIG. 9 , the first board  21  is provided with a pad  61  and a through-hole  62 . The pad  61  and the through-hole  62  are part of a second antenna part  24 . The pad  61  is provided on a second board surface  21   b  (board back surface) of the first board  21 , and is opposed to a resonance stub  43  of a second board  22  (base board). The through-hole  62  penetrates the first board  21  from the first board surface  21   a  to the second board surface  21   b . The through-hole  62  electrically connects the element part  41  to the pad  61 . 
     As shown in  FIG. 9 , a connection part  45  comprises a connection pin  63 . The connection pin  63  is provided at a distal end part of the connection part  45 , and is opposed to the pad  61  of the first board  21 . As shown in  FIG. 8 , in a state where the antenna unit  2  is assembled, the connection pin  63  is brought into contact with the pad  61 , whereby the connection part  45  is electrically connected to the pad  61 . It should be noted that in place of the connection pin  63 , the connection part  45  may be connected to the pad  61  by means of a terminal or other structure. 
     According to the antenna unit  2  configured as described above, the antenna performance becomes hardly lowered as in the case of the first embodiment. That is, the loop antenna  31  and element part  41  are arranged at the same part, and hence the convenience for the user is improved. Further, the loop antenna  31  of the first antenna part  23  and the element part  41  of the second antenna part  24  are positioned in the same plane, and hence the antenna performance of each of the first and second antenna parts  23  and  24  is hardly lowered. 
     Furthermore, it is possible to arrange two antenna parts different from each other in type at the same position, and in the same plane while maintaining the size of the first board  21  (loop antenna board) as it is, and hence it becomes possible to largely reduce the antenna mounting area. 
     The portable computer  1  and antenna unit  2  according to each of the first and second embodiment have been described above. However, the present invention is not limited to the above. Constituent elements according to the respective embodiments may be appropriately combined with each other to be implemented. Furthermore, the constituent elements of the present invention may be modified and embodied in the implementation stage within the scope not deviating from the gist of the invention. 
     While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.