Abstract:
An external input device for a portable computer or personal digital assistant (PDA) has at least one rotatable sideboard. The sideboard operates in two states. When the sideboard is in the first state, the sideboard protects the key sets, and when the sideboard is in a second state, the sideboard facilitates input operation of user.

Description:
This application claims priority of Taiwan Patent Application Serial No. 090119017 filed on Aug. 3, 2001. 
     FIELD OF INVENTION 
     Various aspects of the present invention relate to data input devices for a portable digital processing device. More particularly, various aspects relate to a data input device especially adapted for a personal digital assistant (PDA). 
     BACKGROUND OF THE INVENTION 
     Since the birth of notebook computers, many types of small-sized computers have been produced. A common problem associated with the smaller size, however, is that miniaturized input/output devices (such as keyboards) can be cumbersome, slow and uncomfortable to use. 
     The personal digital assist (PDA), which is typically smaller than a notebook computer, has become very popular in recent years. PDAs typically include a liquid crystal display (LCD) for receiving input and displaying information to the user. Unlike the conventional desktop computer, a PDA does not typically have a conventional keyboard, and has only limited control buttons thereon and a stylus that can be used to input data on the display. The PDA may store handwriting in bitmap or another graphical form, but this technique is typically cumbersome to process, requires a large amount of memory and lowers the efficiency of the PDA. Another method for inputting data to a PDA involves handwriting recognition software installed in the PDA. The PDA encoder translates handwriting to ASCII or another alphanumeric code, and then stores the alphanumeric data. Alternatively, the PDA may have a virtual keyboard. When the virtual keyboard is displayed on the screen, a user can utilize the stylus or control buttons to activate keys within the virtual keyboard to input data. 
     Conventional input methods for PDAs, however, are not typically as efficient as using a conventional computer keyboard. A typical PDA does not include a conventional keyboard because of relatively large size of the keyboard. Various forms of externally-connectable keyboards have been fashioned to work with PDAs, however. When a user wants to input data, the user connects the separable keyboard to the PDA for rapid data entry. 
     There are at least two types of the conventional separable keyboards for PDAs. One type is similar to the conventional computer keyboard, but smaller in size. The other is a foldable keyboard whereby a keyboard is separated into at least two parts that are foldably connected to each other. When the foldable keyboard is not in use, it can be folded and conveniently stored. 
     A common problem with prior art folding keyboards is that key switches in the keyboard foldable keyboards can become deformed when the keyboard is folded. Although the overall height of keyboard is reduced when the keyboard is folded, internal elastic elements (i.e., rubber domes or, springs) used to hold or bias the keyboard in position may deteriorate while the keyboard is folded. One way to solve the problem is to provide higher sidewalls along the rim of the foldable keyboard. The higher side-walls, however, typically block the users&#39; hands when he or she operates the key switches, making the keyboard difficult to operate because the user typically has to lift his/her palms to avoid the sidewalls. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention provides a foldable input device with keys that are not necessarily compressed when the input device is folded up. When a user operates the input device in the extension state, the user is allowed to depress the keys near of the side-wall closest to the user without lifting his/her palms away from the table. 
     Various embodiments of the present invention include a shell that includes a first base having an edge, and a sideboard connected pivotally to the edge. The sideboard has two states. When the sideboard operates in the first state, it is substantially perpendicular to the first base. When the sideboard operates in the second state, it is parallel to the first base substantially. Various embodiments have at least one rotatable sideboard at the side close to the user. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view showing an exemplary sideboard of an exemplary input device operating in a first state; 
     FIG. 2 is a view showing an exemplary sideboard of an exemplary input device operating in a second state; 
     FIG. 3 a  is a side view showing an exemplary sideboard of an exemplary input device operating in a first state; 
     FIG. 3 b  is a side view showing the second exemplary sideboard of an exemplary input device operating in a second state; 
     FIG. 4 is a view showing an exemplary retaining device of an exemplary input device; and 
     FIG. 5 is a view showing an exemplary connecting board of an exemplary input device wherein the connecting board is configured perpendicular to a first base. 
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Referring now to FIG. 1, an exemplary input device includes a shell  100  and a plurality of keys (not shown). The shell  100  includes a first base  101  and a second base  102 . The keys are respectively located on the first base  101  and the second base  102 . The shape of the two bases is not limited to the rectangle base shown in the figure, and variations and modifications (such as oval, angular, rounded or other-shaped bases) may be made without departing from the scope of the present invention. 
     A first base  101  is connected pivotally to a connecting board  103  as shown. Connecting board  103  is connected pivotally to a second base  102 . First base  101  is rotatable and foldable with the second base  102  as appropriate. Sideboards  104  and  105  may be connected pivotally to first base  101  and to second base  102 , respectively. Sideboards  104  and  105  relative to first base  101  and second base  102 , respectively, operate in two states. When sideboards  104  and  105  are operated in the first state, as shown in FIG. 1, sideboards  104  and  105  are substantially perpendicular to the first and second bases  101 ,  102 , respectively. The term “substantially” is meant to compensate for minor design imperfections and other slight deviations (e.g., on the order of about +/−15 degrees). When sideboards  104  and  105  are operated in the second state, as shown in FIG. 2, sideboards  104  and  105  are positioned substantially parallel to the first and second base  101 ,  102 , respectively. Sideboards  104  and  105  are located on the input device approaching the user so that the user&#39;s palms are conveniently supported during operation and data entry. 
     Then, as shown in FIG. 2, the edges of first base  101  and the edges of second base  102 , [not connecting sideboard  104  and connecting board  103  (FIG.  1 ), respectively], make up fixed sidewalls  112 ,  113 ,  114  and  115 . When the keyboard is folded, the edges and sideboards  104  and  105  in the first state are disposed to prevent the keys from depressing each other. The height of sidewalls  112 ,  113 ,  114 , and  115  may be approximately equal to height of sideboards  104  and/or  105 . 
     Referring to FIG. 3 a , a front view shows one embodiment of the present invention operating in the first state. The FIG. 3 b  is a view of second base  102  operating in the second state. The embodiment shown includes a number of keys located on the first and second base  101  and  102 . When sideboard  105  is operated in the second state, for example, a key surface  106  formed by the keys is shown in FIG. 3 b . Relative to the second base  102 , the height of sideboard  105  has a first value A, as shown in FIG. 3 a . The height of surface  106  has a second value B, as shown in FIG. 3 b . The first value A may be designed to be greater than the second value B so as to prevent the keys from being depressed when folding first and second bases  101  and  102  together. Therefore, relative to first base  101 , the height of sideboard  104  has a third value C that is correspondingly greater than the height of the second value B. 
     FIG. 4 is a view of first base  101  and sideboard  104 . Sideboard  104  has a first contact surface  107  configured to touch the edge of the first base  101 . The edge of first base  101  has a protrusion  108  configured to touch sideboard  104 . Protrusion  108  has a second contact surface  109  and a third contact surface  110 . When sideboard  104  is operated in the first state, first contact surface  107  suitably interfaces with the second contact surface  109 . When sideboard  104  is operated in the second state, first contact surface  107  interfaces with third contact surface  110 , as appropriate. Sideboard  104  may be connected pivotally to the protrusion  108  with a shaft  111 , or a hinge, ball joint or other structure. 
     In order to fix sideboards  104  or  105  in the first state when the keyboard is folded, one embodiment of the present invention shown in FIG. 4 has a retaining device. Other embodiments may combine different kinds of the retaining device to selectively fix sideboard  104  in the first state. The following description is based on first base  101 , sideboard  104 , connecting board  103 , and sidewalls  112  and  113 . The same mechanism may be applied to the second base  102  in any convenient manner. 
     Referring again to FIG. 2, the embodiment shown has a projection  117  on sideboard  104  configured to touch connecting board  103 . Connecting board  103  has a depression  116  corresponding to projection  117 , as appropriate. When connecting board  103  is perpendicular to the first base  101  (e.g., as sideboard  104  is in the first state, as shown in FIG. 5) the projection  117  suitably meshes the depression  116 . 
     In another embodiment, the position of the depression and the projection may substitute for each other. That is, depression  116  on connecting board  103  substitutes for the projection (not shown). Projection  117  on connecting board  104  substitutes for the depression (not shown). When connecting board  103  is perpendicular to first base  101  as the sideboard is in the first state, the projection engages with the depression to fix the sideboard so that the sideboard is operated in the first state. In the embodiment of the present invention, it should be noted that the amount of the pair of the depression and the projection is not to be limited to single pair. Various changes may be made in the design and arrangement of the elements described in the exemplary embodiments herein without departing from the scope of the invention as set forth in the appended claims. For example, alternate embodiments may have more than one pair of the depression and the projection on sideboard  104 , or the depression and the projection is disposed on the contact portion between side-wall  112  and sideboard  104 . 
     While this invention has been described with reference to an illustrative embodiment, this embodiment is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiment, as well as other embodiments of the invention, will be apparent upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as falling within the true scope of the invention and its legal equivalents.