Abstract:
A portable computer has a first housing portion having a main body and a second housing portion which is reconfigurable. In the first configuration, the second housing portion is flat and in the second configuration, the second housing portion forms a receptacle for temporarily accommodating one or more option units such as CD-ROM drives or floppy disk drives.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to portable computers designed to be moved easily such as notebook computers, and in particular to a portable computer provided with a mechanism designed to install an option unit such as a floppy disk drive or a CD-ROM drive on the main body thereof. 
     2. Description of the Related Art 
     Notebook computers have been widely used because of easy-to-carry size and weight. Conversely, reduction in size and weight causes difficulties in installation of option units. Therefore, there have been proposed various devices for connecting an option unit to the computer for expansion. 
     In an information processing device described in Japanese Patent Application Laid-Open No. 7-219676, bays for installing option units are formed in the main body. By attaching a dummy box instead of an option unit to be attached, exposed terminals and connectors are protected and the dummy box can also be used to put small articles therein. 
     A disk device described in Japanese Patent Application Laid-Open No. 9-044953 is incorporated in a notebook computer or the like. A stopper for regulating the forward movement from a tray disk replacing position can be moved between a first position projecting further backward from the rear end of the tray and a second position located forward from the rear end of the tray. As a result, the tray can be pulled out from a chassis longer by a moving distance of the stopper. Work for replacing the disk on the tray is thus facilitated. 
     A disk reading device described in Japanese Patent Application Laid-Open No. 9-204763 is designed to be capable of being attached to an electronic device in place of another external peripheral device. When a disk having such a size that the disk cannot be housed in the disk reading device is to be reproduced, reproduction is conducted in such a state that a drawer supporting the disk is pulled outside the main body of the disk reading device. 
     A separate function expanding device of a portable electronic device described in Japanese Patent Application Laid-Open No. 9-265336 is formed so that a portion corresponding to a port replicate device and another portion corresponding to an expansion unit may be separated. In the portion corresponding to the port replicate device, a locking means is provided. Accessory devices are thus made thin. 
     Eventually in these conventional devices, it is necessary to add parts, pull out a tray, or separate an expansion unit portion. When using options, the portability is reduced. 
     As other conventional examples, personal computers of built-in option type, cable connection type, and stack type using a docking station are known. In the personal computer of built-in option type, the external shape of the device is large and the weight is heavy, resulting in hampered portability. In the personal computer of cable connection type, since the floppy disk drive is not fixed, the floppy disk drive cannot be used in traveling. 
     In the personal computer of stack type having a docking station, traveling can be done while using the floppy disk drive or the CD-ROM drive mounted on the docking station. In this case, however, the weight and volume of the device as a whole are increased by not only the weight and volume of the floppy disk drive or the CD-ROM drive but also the weight and volume of the docking station. As a result, the portability is hampered. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide such a mechanism that the portability is not reduced when attaching an option unit to the computer. 
     According to the present invention, a portable computer is comprised of a main body thereof and a recloseable receptacle coupled to bottom of the main body, for accommodating at least one option unit when the reclosable receptacle is opened, wherein a flat bottom is provided to the main body with the reclosable receptacle closed. 
     The reclosable receptacle may comprise a first plate and a second plate which are rotatably coupled to each other through a hinge to form a space for accommodating at least one option unit when the reclosable receptacle is opened. The first plate is kept perpendicular to the bottom of the main body and the second plate is kept parallel to the bottom of the main body when the reclosable receptacle is opened. 
     The reclosable receptacle forms an option accommodation space when opened and the bottom of the main body becomes flat when closed. Therefore, an option unit that cannot be accommodated within the main body can be attached to the main body by opening the reclosable receptacle. After removal of the option unit, the reclosable receptacle can be closed to provide a flat bottom to the main body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a perspective view of a notebook computer in a state that no option unit is attached thereto according to an embodiment of the present invention; 
     FIG. 1B is a perspective view of a notebook computer in a state immediately before attaching options thereto according to the embodiment; 
     FIG. 1C is a perspective view of a notebook computer in a state that options have been attached thereto according to the embodiment; 
     FIG. 2 is a perspective view of an installation mechanism employed in the embodiment in a closed state; 
     FIG. 3 is a perspective view of the installation mechanism employed in the embodiment in an opened state; and 
     FIG. 4 is a partial side view of a notebook computer in a state that options have been attached thereto according to the embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIG. 1A, a notebook computer  1  is composed of a main body  10 , and a reclosable bottom portion  20  provided on the bottom of the main body  10 . The reclosable bottom portion  20  has a hinge mechanism by which the reclosable bottom portion  20  can be freely opened and closed. When accommodating or attaching option units, the reclosable bottom portion  20  is brought to an opened state to form a receptacle. After the option units have been removed, the reclosable bottom portion  20  passes to a closed state. In other words, the reclosable bottom portion  20  can switch between two states, i.e., the closed state and opened state owing to the hinge mechanism. 
     As shown in FIG. 1B, the reclosable bottom portion  20  is divided into a bottom plate  201  and a connector plate  202  which are rotatably connected through a hinge portion  203 . When attaching two option units (hereinafter, a floppy disk drive  101  and a CD-ROM drive  102  are taken as an example) to the main body  10 , the reclosable bottom portion  20  is brought to the open state by the hinge mechanism, as will be described in detail. This forms a space for attaching the floppy disk drive  101  and the CD-ROM drive  102  to the main body  10 . 
     Needless to say, in addition to the option accommodation function, the main body  10  further has various functions for serving as a computer. In other words, the floppy disk drive  101  and the CD-ROM drive  102  are not permanently mounted on the main body  10 . When closed, the reclosable bottom portion  20  provides the flat bottom of the notebook computer  1 . Furthermore, each of the floppy disk drive  101  and the CD-ROM drive  102  has a packed form to facilitate the attachment. 
     As shown in FIG. 1C, when attaching the floppy disk drive  101  and the CD-ROM drive  102  to the main body  10 , the reclosable bottom portion  20  is opened to form the option accommodation space on the bottom of the notebook computer  1 . The option units (here, the floppy disk drive  101  and the CD-ROM drive  102 ) can be inserted into the space or bay formed by opening the reclosable bottom portion  20 . 
     Referring to FIG. 2, the reclosable bottom portion  20  is composed of the hinge portion  203  and a hinge portion  204 , which provide a hinge mechanism. Furthermore, the reclosable bottom portion  20  has the bottom plate  201  and the connector plate  202  which are rotatably connected through the hinge portion  23 . The connector plate  202  has a floppy disk drive connector  205  and a CD-ROM drive connector  206  fixed thereon. 
     The floppy disk drive connector  205  is electrically connected to the computer circuit mounted in the main body  10  through a cable  207 . Therefore, the floppy disk drive connector  205  causes the floppy disk drive  101  to be mechanically and electronically connected to the main body  10 , and thereby data and control signals are transferred between the floppy disk drive  101  and the computer circuit of the main body  10 . 
     Similarly, the CD-ROM drive connector  206  is electrically connected to the computer circuit mounted in the main body  10  through a cable  208 . Therefore, the CD-ROM drive connector  206  causes the CD-ROM drive  102  to be mechanically and electronically connected to the main body  10 , and thereby data and control signals are transferred between the CD-ROM drive  102  and the computer circuit of the main body  10 . 
     In addition, the bottom plate  201  has a supporting column  209  for securing the option accommodation space when the reclosable bottom portion  20  is opened. One end of the supporting column  209  is rotatably connected to the bottom plate  201  to be raised straight up so as to be able to maintain the opened state of the reclosable bottom portion  20 . The other end of supporting column  209  is bent to form a supporting portion  210  that is used to lock the bottom plate  201  in place. The hinge portion  203  rotatably couples the bottom plate  201  to the connector plate  202  such that the bottom plate  201  can rotate up to 90 degrees with respect to the connector plate  202 . The hinge portion  204  rotatably couples the connector plate  202  to the main body  10  such that the connector plate  202  can rotate up to 90 degrees with respect to the bottom of the main body  10 . 
     Referring to FIGS. 3 and 4, the reclosable bottom portion  20  can be bent until the connector plate  202  becomes perpendicular to the bottom plate  201  with the hinge portion  203  serving as the boundary. Since the hinge portion  204  couples the connector plate  202  to the main body  10 , it is made possible to bend the connector plate  202  with respect to the bottom plate  201  from the horizontal state to the vertical state. The bottom end of the supporting column  209  is fixed to the bottom plate  201  of the reclosable bottom portion  20 , and it can be moved up to the state shown in FIG.  3 . The supporting portion  210  of the supporting column  209  can come into contact with the bottom of the main body  10  when the supporting column  209  is raised (see FIG.  4 ). The supporting column  209  thus functions to make the bottom plate  201  always parallel to the main body  10 . 
     By referring to FIGS. 1A through 1C, an operation of the embodiment will now be described. First of all, in the state of FIG. 1A, any option unit cannot be used. In the case where a floppy disk drive and a CD-ROM drive are needed, the reclosable bottom portion  20  is moved downward until the connector plate  202  becomes perpendicular to the main body  10 . Here, the supporting column  209  functions to keep the bottom plate  201  of the reclosable bottom portion  20  parallel to the main body  10 . In this way, the notebook computer  1  comes into the state shown in FIG.  1 B. At this stage, the space for accommodating the floppy disk drive  101  and the CD-ROM drive  102  has been secured. Accordingly, the floppy disk drive  101  is inserted and connected to the floppy disk drive connector  205 . Similarly, the CD-ROM drive  102  is inserted and connected to the CD-ROM drive connector  206 . At this stage, the notebook computer  1  comes into the state shown in FIG. 1C or FIG. 4, and it becomes possible to use a floppy disk and a CD-ROM. 
     By the way, as option units other than the floppy disk drive and the CD-ROM drive, a battery pack, a hard disk drive, and a drive for a recording medium such as a DVD-ROM can also be attached to the main body  10  using the embodiment according to the present invention. 
     As described above, the present invention brings about the following advantages. Since a space can be dynamically formed within a notebook computer, option units such as a floppy disk drive and a CD-ROM drive can be incorporated in the notebook computer which originally cannot incorporate them. 
     Furthermore, when using option units, neither a cable nor a docking station is required. This results in an effect that excellent portability is maintained even when option units are used.