Abstract:
In one embodiment, the invention provides a pen-based computing system. The system comprises a tablet unit including a display screen and an electronic assembly housed within an enclosure; and a separate base unit including two panels connected via a hinge, a first one of the panels bearing a keyboard, and a second one of the panels being arcuately displaceable relative to the first panel to prop the tablet unit in a viewing position in which the display screen makes a viewing angle with the keyboard of greater than 90 degrees, wherein the tablet unit and the first panel have complementary formations to prevent sliding movement of the tablet unit relative to the first panel when in the viewing position.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to mobile computing devices. In particular it relates to pen-based mobile computing devices.  
         BACKGROUND  
         [0002]    Pen-based computing systems, unlike conventional laptop or notebook computers, allow data input via a stylus or pen. Briefly, a pen is used to write characters on a portion of the display screen that includes a digitizer. The digitizer captures the handwriting and handwriting recognition software converts the software into recognized text.  
           [0003]    During data entry using the keyboard, a viewing angle made between the display screen and the keyboard should be greater than 90 degrees for optimal viewing of the display screen.  
           [0004]    Thus, there should be some mechanism to hold the display screen relative to the keyboard at the correct viewing angle.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIGS. 1A to  1 E show various view of a computing system, in accordance with one embodiment of the invention;  
         [0006]    [0006]FIG. 2 shows a side view of the system of FIG. 1, when in a laptop mode configuration;  
         [0007]    [0007]FIGS. 3A and 3B show views of a complementary formation mounted on the tablet unit of the system of FIGS. 1A to  1 E to prevent sliding movement of the tablet unit, in accordance with one embodiment of the invention;  
         [0008]    [0008]FIG. 4A shows the complementary formation of FIGS. 3A and 3B when in a stowed position;  
         [0009]    [0009]FIG. 4B shows the complementary formation of FIGS. 3A and 3B when in an extended position;  
         [0010]    [0010]FIG. 5A shows a top view of the system of FIGS. 1A and 1E, when in the laptop mode configuration;  
         [0011]    [0011]FIG. 5B shows a complementary formation of a base unit of the system of FIGS. 1A to  1 E, in accordance with one embodiment of the invention;  
         [0012]    [0012]FIG. 5C illustrates how the complementary formation of the base and tablet units cooperate, in accordance with one embodiment;  
         [0013]    [0013]FIG. 6A shows a top plan view of the system of FIGS. 1A to  1 E, in the laptop mode configuration in which complementary formations of the base unit, in accordance with another embodiment of the invention, may be seen; and  
         [0014]    [0014]FIG. 6B illustrates the operation of the complementary formation of the embodiment shown in FIG. 6A.  
     
    
     DETAILED DESCRIPTION  
       [0015]    In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the invention can be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to avoid obscuring the invention.  
         [0016]    Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.  
         [0017]    [0017]FIGS. 1A to  1 E show various views of a computing system  10  in accordance with one embodiment of the invention. The system  10  is a pen-based computing system and includes a tablet unit  12  and a base unit  14 . The base unit  14  includes first and second generally planar panels  16 ,  18 , respectively. The panels  16 ,  18  are connected by a flexible hinge  20  which permits relative articulation between the first and second panels  16 ,  18 . The first panel  16  bears a keyboard  22  which permits data entry into the tablet unit  12  when the system  10  is operated in a laptop mode.  
         [0018]    As can be seen in FIGS. 1B, 1C, and  1 D of the drawings, the system  10  may be positioned in a carry mode configuration, in which the tablet unit  12  is positioned over the first panel  16  with the second panel  18  of the base unit  14  positioned over the tablet unit  12 . In order to secure the system  10  in the carry mode configuration, the second panel  18  of the base unit  14  includes two pivotally mounted latches  24  which engage complementary locking formations provided in the tablet unit  12  to releaseably lock the second panel  18  to the tablet unit  12 . It will be noted that, in the carry mode configuration, the system  10  resembles a portfolio (see FIG. 1D of the drawings).  
         [0019]    Components of the tablet unit  12  typically include one or more processing components, a memory hierarchy comprising a number of memory devices, and a display screen  24  including a digitizer.  
         [0020]    [0020]FIG. 2 of the drawings, shows a configuration of the system  10  that is used for data entry via the keyboard  22 . This configuration is known as the laptop mode configuration and comprises the tablet unit  12  held at an inclined position relative to the first panel  16  so that the display screen  24  of the tablet unit  12  makes a viewing angle α with the keyboard  22  of greater than 90 degrees. In the laptop mode configuration, the tablet unit  12  is propped by the second panel  18  of the base unit  14  which is releaseably secured thereto via the latches  24  described above.  
         [0021]    It will be appreciated that when in the laptop mode configuration, a leading edge  26  of the tablet unit  12  has to be arrested to prevent sliding movement thereof relative to the base unit  14 . Accordingly, in one embodiment of the present invention, there is provided complementary formations on the tablet unit  12 , and the base unit  14 , to prevent sliding movement of the tablet unit  12  relative to the first panel  16 , when the system  10  is in the laptop mode configuration, as shown in FIG. 2 of the drawings. In one embodiment, as shown in FIGS. 3A and 3B of the drawings, the complementary formations of the tablet unit  12  include a male formation which defines a spigot  30 . The spigot  30  is pivotally secured to the tablet unit  12 , for example using a transverse pivot pin (not shown) and may be operated to articulate between a stowed position in which it is completely within the housing or enclosure of the tablet unit  12  (see FIG. 4A), and an extended position in which it protrudes from the housing as is shown in FIG. 4B. As can be seen from FIG. 3A of the drawings, the spigot  30  includes a thin neck region  32  and an enlarged head  34 .  
         [0022]    In order to receive the spigot  30 , the base unit  14  includes a complementary female formation shaped and dimensioned to receive the spigot  30  in snug fit therein. As will be seen from FIG. 5A of the drawings, in one embodiment, the base unit  14  includes a plurality of female formations  36  disposed along the longitudinal axis. Each of the female formations  36  may be selectively engaged by a spigot  30  to secure the tablet unit  12  when in the laptop mode configuration. It will be appreciated that the plurality of female formations  36  allows for selection of different viewing angles.  
         [0023]    [0023]FIG. 5B of the drawings shows one of the female formations  36  of the FIG. 5A in greater detail. As will be seen, the female formation  36  includes two sliding members  40  which are mounted within a recess in the base unit  14  to define a transverse slot  42  within which the spigot  30  is receivable. The sliding members  40  are biased under the influence of a biasing element to close the transverse slot  42  therebetween. In one embodiment, the biasing element may include a coil spring. In use, the spigot  30  urges the sliding members to move in an outward direction indicated by the arrows  44  in FIG. 5B to allow the enlarged head  34  of the spigot  30  to be received in the transverse slot  42 . Thereafter, under influence of the biasing force of the biasing elements, the sliding members  40  close behind the enlarged head  34  to bear against the neck  32  of the spigot  30 , thus locking the spigot  30  to the female formation  36 . In one embodiment, the head  32  of the spigot  30  and the sliding members  40  may be contoured to allow the head  32  to move into the slot  42  with minimal force. For example, the edges of the sliding members  40  adjacent the transverse slot  42  may be inclined to guide the head  34  into the slot  42 .  
         [0024]    The complementary formations on the tablet unit  12 , and the base unit  14 , need not be male-female type formations. For example, as can be seen in FIGS. 6A and 6B of the drawings, the complementary formations of the tablet unit  12  may include a rotatable member in the form of a wheel  50  having a plurality of circumferencially spaced teeth  52 . In this embodiment, the complementary formations of the base unit  14  may then include an elongate track  54  provided with complementary teeth to engage the teeth  52  of the wheel  50 . As can be seen in FIG. 6A of the drawings, in one embodiment, the tablet unit  12  includes two laterally-spaced wheels  50  and the base unit  14  includes two corresponding tracks  54  to receive the wheels  50  therein. Instead of the discrete new angles provided by the embodiment described with reference to FIGS. 5A to  5 C of the drawings, the embodiment shown in FIGS. 6A and 6B provide a continuous range of viewing angles each of which is defined by the position of the wheels  50  within the tracks  54 .  
         [0025]    In an embodiment not shown, in order to prevent sliding movement of the tablet unit  12  relative to the first panel  16  of the base unit  14 , the first panel  16  may include a non-slip or high friction surface. Further, portions of the tablet unit that contact the panel  16  when the system  10  is in the desktop mode configuration may include a rough or serrated surface to further prevent sliding of the tablet unit  12  relative to the panel  16 .  
         [0026]    Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that the various modification and changes can be made to these embodiments without departing from the broader spirit of the invention as set forth in the claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than in a restrictive sense.