Abstract:
A handheld computer keyboard system for use in conjunction with small computerized apparatus such as Personal Digital Assistants (PDAs) features a keyboard, a cover, and an I/O connector to allow a computerized apparatus to be connected to the keyboard. The system also features a retractable stabilizing leg for greater stability when the system is set on a flat surface. The system allows a user to input text and data into a device such as a PDA, which typically must be done with a stylus, with a more convenient keyboard. The cover for the system closes to protect the keyboard and provides a support easel for the PDA when the system is in use.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 09/251,847 filed on Feb. 17, 1999 that claims the benefit of U.S. Provisional Patent Application No. 60/104,172 filed on Oct. 13, 1998. This application is also related to U.S. patent application Ser. No. 29/100,882 filed on Feb. 18, 1999, incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     The present invention relates to keyboards for electronic devices and, more particularly, to keyboard accessories for handheld electronic devices such as personal digital assistants (PDAs). 
     2. The Relevant Art 
     Small personal organizers, personal digital assistants (PDAs), palm-size computers, combination phone/computers and other devices that are commonly termed “pen-based computers” often rely on the use of a stylus for data entry. The two most common methods for data entry utilizing a stylus are 1) tapping on an “on-screen software keyboard” and 2) hand writing on a pressure-sensitive layer. In the first method the electronic device displays a keyboard, buttons, or other indicia on a pressure sensitive screen, and the user selects the desired option by tapping an appropriate location with the stylus. In the second method the user moves the stylus across a pressure-sensitive surface to form characters. In this latter method, known as “handwriting recognition,” the device must “recognize” the characters formed by the user on the pressure-sensitive surface. Handwriting recognition affords the user greater flexibility and speed in making notations and composing messages, but has been prone to errors in recognition. 
     Pen-based computers have grown in popularity for several reasons, chief amongst them being their small size and easy portability. Miniaturization of electronic components has made these devices increasingly powerful, versatile, and affordable. Many users, however, find the two available stylus data-entry methods cumbersome and prone to errors. The tapping method is typically slow, and the small screen area of PDAs increases the likelihood that a user will inadvertently make unintended selections. 
     The handwriting recognition method affords the user greater flexibility and ease of use over the tapping method for composing messages and entering data, but handwriting recognition has its own set of limitations. The character recognition programs at the heart of these handwriting recognition methods often need to learn the handwriting of the user in order to be effective. Many users do not have the time or patience to bring their pen-based computer through this learning process. Even those users that do train their pen-based computers to recognize their handwriting find that mistakes are unavoidable since the art of handwriting recognition is far from perfect. Errors will also be more common if the user attempts to use the device in a moving vehicle such as a car or train since the motion of the vehicle makes it more difficult to maintain one&#39;s handwriting style. Further, a pen-based computer trained to recognize one individual&#39;s writing style will not function well if transferred to a second user, and may never function well if several users routinely use it. Most users of pen-based computers are already familiar with common keyboard designs as used on typewriters, standard computers, 10-key data entry devices, telephone keypads, and the like. Users are generally comfortable with using keyboards for composing text and entering data into electronic devices. It may therefore be desirable to attach a keyboard to PDAs and other pen-based computers in order to facilitate text and data entry. 
     To address some of these problems the Apple Newton PDA had an available accessory keyboard. The Newton PDA&#39;s keyboard, however, is attached to the Newton PDA by way of a somewhat cumbersome cable. Further, Newton PDA&#39;s keyboard was unprotected from damage during transport, unless it was inserted into a separate carrying case. Finally, the Newton PDA itself needed to be propped up or positioned for proper viewing when using the accessory keyboard. 
     SUMMARY OF THE INVENTION 
     This present invention is a handheld computer keyboard system for use in conjunction with small computerized apparatuses that typically do not have permanently attached keyboards. In one embodiment the system consists of a keyboard hinged to a cover and an interface assembly including an I/O connector configured to engage an I/O port of a computerized apparatus. In another embodiment the system also incorporates a stabilizing leg which may slide out from a recess in the back of the keyboard. The stabilizing leg is advantageous for providing support to the system in use such that the weight of the attached apparatus, use of a stylus, or incidental jostling does not tip the system over. 
     In another embodiment the hinge between the keyboard and the cover allows the cover to be opened to any one of several open positions so that the user may select the best angle for optimal viewing and use. The stabilizing leg in this embodiment slides rearwardly out from a recess in the back of the keyboard. This aspect is advantageous as it protects the stabilizing leg when not in use, and reduces the size of the keyboard. 
     The interface assembly is preferably attached to, and moves with, the cover portion so that the cover additionally serves to stabilize the attached computer apparatus regardless of the chosen open position. In one embodiment, the I/O connector is intended to engage the I/O connector of a personal digital assistant (PDA). 
     The keyboard is preferably arranged in the common QWERTY layout and a plurality of additional buttons are arranged above the numeral keys, although other keypad and keyboard layouts are also used. These additional buttons are designed to have programmable functionality such that the user may associate with each button one or more computer commands that will be executed when the button is depressed. 
     While these embodiments are aimed at providing a convenient portable keyboard for use with PDAs, other embodiments are envisioned that utilize less common keyboard designs, that are specific to other types of computerized apparatus of a similar form-factor, and that incorporate additional features such as additional I/O connectors, wireless modems, Global Positioning Satellite (GPS) receivers, and the like. 
     The present invention is advantageous to users of PDAs in that it provides them a better option for interacting with their PDAs. The use of a keyboard is more effective for most people than pen-based systems. The use of a keyboard instead of a stylus allows users to enter text and data more quickly and with a lower error rate. These advantages become more important when a PDA is used in a moving vehicle or by individuals with less steady hands, or by users who have not conditioned the PDA to recognize their own handwriting. 
     The availability of buttons with programmable functionality allows users to customize their keyboard system to streamline repetitive tasks. The cover serves to protect the keyboard when closed. When open, the cover serves as an easel to support the attached PDA in a desired viewing position. When the PDA is attached and the stylus is used, the cover provides a back support so that lateral forces are not transmitted to the I/O connector. The stabilizing leg provides overall stability to the keyboard system to prevent the keyboard system from tipping over from the weight of the PDA from pressures applied to the PDA, or from accidental jostling, or from the motion of a vehicle such as an airliner or train. 
     These and other aspects and advantages of the present invention will become more apparent when the Description below is read in conjunction with the accompanying Drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, with like reference numerals designating like elements. 
     FIG. 1 is a perspective view of a keyboard system of the present invention with the cover portion open; 
     FIG. 2 is a side elevational view of the keyboard system of FIG. 1; 
     FIG. 3A is a top plan view of the keyboard system of FIG. 1; 
     FIG. 3B is an enlarged view of the interface assembly, encircled by line  3 B of FIG. 3A; 
     FIG. 4A is a partial cross-sectional view of the connector taken along line  4 A  4 A of FIG. 3B; 
     FIG. 4B is a partial cross-sectional view similar to that of FIG. 4A where the hinge mechanism is provided with a detent assembly; 
     FIG. 5 is a perspective view of the base of the keyboard portion showing the stabilizing leg in the fully retracted position; 
     FIG. 6 is a perspective view, similar to FIG. 1, of a keyboard system of the present invention with a PDA engaged with the interface assembly; 
     FIG. 7 is a side elevational view, similar to FIG. 2, of a keyboard system of the present invention with a PDA engaged with the interface assembly; 
     FIG. 8A is a side elevational view of the keyboard system of FIG. 1 with the cover portion opened to 90°; 
     FIG. 8B is a side elevational view of the keyboard system of FIG. 1 showing the cover portion opened to several viewing positions; 
     FIG. 8C is a side elevational view of the keyboard system of FIG. 1 showing the cover portion opened to 135°; 
     FIG. 9 is a top plan view of the keyboard system of FIG. 1 with the cover portion closed and the stabilizing leg fully extended; 
     FIG. 10 is a perspective view of the keyboard system of FIG. 1 in its closed orientation; 
     FIG. 10A is a detailed partially broken view taken along line  10 A of FIG. 10; 
     FIG. 11A is a perspective view of the keyboard system with a non-standard keypad and an easel stabilizing leg; 
     FIG. 11B is a side elevational view of the keyboard system in FIG.  11 A. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a keyboard system  10  of the present invention including a cover portion  12 , a keyboard portion  14 , and a connector assembly  19 . The keyboard portion  14  has a keypad  16  and additional buttons with programmable functionality  18  arranged above the keypad  16  to either side of the connector assembly  19 . Another feature that may be placed on the keyboard portion  14  is one or more stylus receptacles  21 . These components of the keyboard portion  14  are supported by a base  27 , which preferably is made of a hard plastic material. While FIG. 1 shows the preferred arrangement of the components of keyboard portion  14 , other embodiments have different component arrangements. 
     The keypad  16  is preferably an alphanumeric keypad and may be arranged according to any number of standard or non-standard designs. The most common standard design, known to those skilled in the art of keyboard designs as QWERTY, is a preferred embodiment. Alternately, the keypad may be a 10-key design for data entry or inventory control. Other embodiments include keypads specially designed to meet specific applications. For example, self-guided tours of a facility can be provided on a PDA-like computer apparatus that attaches to the present keyboard system with keys for specific functions such as “Show Map” and “Tell Me More.” Buttons with programmable functionality  18  are also preferably provided. These buttons allow the user to associate with each key one or more computer commands that will be executed when the button is depressed. In the art, a series of computer instructions associated with a single key or simple command is commonly termed a macro. The ability to execute macros allows the user to take a commonly used and often times lengthy series of computer instructions and run them with the touch of a single button, thus saving the user time by eliminating keystrokes. The implementation of programmable buttons and macros are well known to those skilled in the art. 
     In the preferred embodiment the associated computer commands are stored by non-volatile memory when the keyboard system is not in use. Such memory logic for keyboards is well known in the art and commercially available. The preferred embodiment of the present invention draws power from the attached PDA in order to operate the keys of the keypad  14  and the buttons with programmable functionality  18 . It is advantageous to draw power from the PDA as this eliminates the need for an external power supply or batteries and thus reduces weight and simplifies the use of the keyboard system  10 . It is further advantageous for the keyboard system  10  to draw power from the PDA as this guarantees that the keyboard system  10  will always operate whenever the PDA has power. Suitable keyboard controllers are available from a variety of vendors. 
     FIG. 2 shows a side elevational view of the keyboard system of FIG.  1 . When the keyboard portion  14  is placed on a flat surface the points of contact between the base  27  and that surface define an imaginary plane hereinafter known as the support plane  24 . The points of contact that define the support plane  24  may be specially designed dimples on the exterior of the base  27 , or they may be small resilient pads attached thereto. Alternately, the entire exterior of the base  27  may be planar, in which case the base  27  and the support plane  24  would be coplanar. In such an embodiment the exterior surface of the base  27  may be textured to provide increased resistance to slipping and shifting. 
     In addition to the cover portion  12 , the keyboard portion  14 , and the interface assembly  19 , FIG. 2 also shows a stabilizing feature in the form of a stabilizing leg  22  intended to prevent the keyboard system from tipping over backward. In the preferred embodiment the stabilizing leg  22  retracts into a recess within the keyboard portion  14  when the keyboard system  10  is not in use. When the keyboard system  10  is in use the stabilizing leg  22  is fully extended, such that the bottom surface of the stabilizing leg  22  is coplanar with the support plane  24 . 
     The value of the stabilizing leg  22  design is several-fold. First, normal use of the keyboard system  10  is not likely to accidentally cause the stabilizing leg  22  to retract into the retracted position. Secondly, the preferred design for the stabilizing leg  22  allows for a large percentage of the bottom surface of the stabilizing leg  22 , which is coplanar with the support plane  24 , to be in physical contact with the surface on which the keyboard system  10  is resting, providing greater stability to the keyboard system  10 . Such stability is provided both in terms of resistance to tipping and well as resistance to sliding and shifting. Additionally, a stabilizing leg  22  designed to extend from the keyboard portion provides good stability regardless of the position of the cover portion  12 . Another embodiment of a stabilizing feature is an easel leg  26  as will be described with reference to FIGS. 11A and 11B. 
     FIG. 3A is a top plan view of the keyboard system of FIG.  1 . Line  3 B encircles the interface assembly  19 , which is shown in an enlarged fashion in FIG.  3 B. The interface assembly  19  is preferably fixed to the cover portion  12  and has a hinge connection on either side to allow the keyboard portion  14  to be pivotally connected to the cover portion  12  as will be described in more detail in reference to FIG.  4 A. 
     An I/O connector  20  is mounted to the top of the interface assembly  19  as best seen in FIG.  3 B. The I/O connector  20  in the preferred embodiment is designed to mate to the I/O port of a 3COM Palm III PDA. In other embodiments the I/O connector  20  would be specifically configured to other PDAs and other specific pen-based computers. Another embodiment would have an I/O connector  20  that was adaptable to more than one pen-based computer design. The specifications for the Palm III PDA is available from 3COM Corporation. 
     FIG. 4A is a partial cross-sectional view of the connector taken along line  4 A— 4 A of FIG. 3B illustrating the hinge mechanism connecting the cover portion  12  to the keyboard portion  14 , and more particularly to the base  27  of the keyboard portion  14 . In the preferred embodiment the interface assembly  19  is fixed to the cover portion  12 , thus the pivotal connection between the interface assembly  19  and the base  27  allows the cover portion  12  and interface assembly  19  to move together as the cover portion  12  is opened and closed. In order that the user may communicate to the computer apparatus by way of the keypad  16  and the buttons with programmable functionality  18 , a cable comprising multiple wires  29  connects the I/O connector  20  to the control circuitry (“keyboard controller”) of the keyboard portion  14 . The cable also carries power from the I/O connector  20  to the keyboard controller (not shown). These wires  29  are routed from the I/O connector  20  through the interior of the interface assembly  19 , through the hinge on the side of interface assembly  19  and into the matching hinge connector on the keyboard portion  14 . These wires  29  arc shown in FIG. 4A passing through a sheath located along the axis of the hinge on the right side of the interface assembly  19 . Other embodiments pass wires  29  through the left hinge or through both hinges. The sheath for the wires  29  shown in FIG. 4A helps prevent the wires  29  from interfering with the motion of the hinge and also prevents the wires  29  from rubbing and fraying. 
     FIG. 4B shows an enlarged view of one of the hinge connectors in FIG.  4 A. In this view one possible design for a detent feature is illustrated. In this design the exterior surface of the hinge connector on the interface assembly  19  has one or more hemispherical depressions or “dimples.” A cylindrical well on the corresponding hinge connector contains a spring and a spherical ball. When the interface assembly  19  is pivoted relative to the keyboard portion  14  the rotation around the axis will come to a stop when the spring-loaded ball meets a hemispherical depression. Application of sufficient rotational force to the hinge will push the ball back up into the cylindrical well against the pressure of the spring and allow the interface assembly  19  to freely rotate again. 
     By using such detents in the hinge connector the interface assembly  19  may be made to lock at one or more positions relative to the keyboard portion  14 . In the preferred embodiment the interface assembly is fixed to the cover portion  12 , thus the use of detents in the hinge connector effectively allows the cover portion  12  to be locked at one or more predetermined angles relative to the keyboard portion  14 . It should be noted that many different methods for creating detents are known in the art and other embodiments of this invention may take advantage of these alternative designs. 
     FIG. 5 shows the base  27  of the keyboard portion  14  beneath the keypad  16 . Attention is directed to the stabilizing leg  22  shown fully retracted into the interior of the keyboard portion  14 . The stabilizing leg  22  may be withdrawn through an opening in the back of the base  27  of the keyboard portion  14 , shown as  22 ′. The stabilizing leg  22 , as shown in FIG. 5, is T-shaped with a cross-member, a central leg, and two prongs on either side of the central leg. The central leg features two guide rails that are engaged by two corresponding notches in a support member on the interior of the keyboard portion  14 . Each of the two prongs has a barb-shaped end so that when the stabilizing leg  22  is extended for use it can not be pulled completely out of the keyboard portion  14 . Each prong additionally has a series of notches as part of a detent system. A corresponding component on the interior of the keyboard system  14  engages the notches on the stabilizing leg prongs causing the stabilizing leg  22  to have one or more locked positions. The advantage of such a locked position is that it helps prevent the stabilizing leg  22  from unintentionally being pushed back into the keyboard section  14 . 
     FIG. 6 is a perspective view of the keyboard system of FIG. 1 showing a Personal Digital Assistant (PDA) attached to the I/O connector. In the preferred embodiment the inner surface of the cover portion  12  has vertical ribs  25  with a spacing between them just wide enough to accommodate and stabilize a PDA attached to the I/O connector  20 . These vertical ribs  25  also add rigidity to the cover portion  12 . 
     FIG. 6 additionally shows on the top left and top right corners of the keyboard portion  14  stylus receptacles  21  intended to hold a PDA stylus. In the illustration the stylus receptacle  21  on the right side of the keyboard portion  14  holds a stylus. While the preferred embodiment contains a stylus receptacle  21  on either side of the keyboard portion  14  for the convenience of both right and left-handed users, other embodiments of the keyboard system  10  would not contain such receptacles where the keyboard system  10  was for use with a computer apparatus that did not ordinarily need a stylus. Other embodiments contain only one receptacle  21  due to design constraints imposed by the style and placement of the keypad  16  on the keyboard portion  14 . Additional embodiments place the stylus receptacle  21  on the inside of the cover portion  12  on either or both sides of the intended location for the computer apparatus. 
     FIG. 7 is a side elevational view of the keyboard system of FIG. 1 supporting a PDA. The illustration shows one of two side flaps  23  on either side of the cover portion  12  that provide rigidity to cover portion  12  and further serve to protect the keyboard portion  14  from side entry of dirt, dust, and fluids when the cover portion  12  is closed. Additionally, the side flaps contain a latch mechanism  32  which will be discussed in detail with reference to FIG.  10 A. 
     FIGS. 8A-8C are side elevational views of the keyboard system of FIG. 1 with the cover portion  12  opened to different positions. As shown, rotation around the axis of a hinge allows the cover portion  12  to move from a closed position wherein the angle between the plane of the cover and the support plane  24  is 0°, and any number of open positions wherein the angle between the plane of the cover and the support plane  24  is at least 90° and preferably 135°, which would place the cover such that it would support a  3 COM Palm PDA at the recommended viewing angle. The cover, which serves as a support easel for the PDA, is supported in these multiple positions by the aforementioned detent mechanism. Preferably, the hinge is part of the interface assembly  19  as described above with reference to FIG. 4A, however in other embodiments this is not necessarily so. In other embodiments the hinge may be designed as a separate component from the interface assembly  19 , or alternately, the cover portion  12  may attach to the keyboard portion  14  by hinges directly attached to both pieces. 
     FIG. 9 is a top plan view of the keyboard system of FIG. 1 with the cover portion closed and the stabilizing leg  22  fully extended. In this perspective the stabilizing leg  22  can be seen to have a semicircular cut-out in the middle of its cross-member. This feature is designed to allow the stabilizing leg  22  to be grasped firmly by the customer s and also reduces the overall weight of the keyboard system  10 . 
     FIG. 10 is a perspective view of the keyboard system of FIG. 1 in its closed orientation. The side flaps  23 , discussed above in reference to FIG. 7, in the preferred embodiment contains a latch mechanism  32 . The latch mechanism is shown in greater detail in FIG.  10 A and consists of a small tab  31  on the inside of the side flap  23  and a corresponding indentation on the exterior of the base  27 . When the tab  31  is engaged in the corresponding indentation the cover closes securely such that it is not easily opened accidentally. Tab  31  is shown in FIG.  1 . In other embodiments of the present invention the latch mechanism  32  is placed on the front edge of the cover portion  12 , and still other embodiments do not contain a latch at all. Further, some embodiments also do not contain side flaps  23 . 
     FIGS. 11A and 11B are perspective and side elevational views, respectively, of the keyboard system  10  with a non-standard keypad and an easel leg  26  rather than a stabilizing leg  22 . As noted previously, the preferred embodiment of the present invention incorporates a standard QWERTY keypad  16 , however other embodiments of the invention utilize other keypad options. As shown in FIG. 11A, alternative keypad  16  designs, for example the 10-key layout frequently used in inventory control, would not require as wide of a keyboard portion  14  as the preferred embodiment. 
     The stabilizing feature shown in FIGS. 11A and 11B is in the form of an easel leg  26  that folds flush against the exterior surface of the cover portion  12 . When the keyboard system  10  is in use, the easel leg  26  folds out to an open position as shown in FIGS. 11A and 11B. In another embodiment of the invention, the easel leg  26  folds into a recessed portion on the exterior surface of the cover portion  12 . Like the stabilizing leg  22 , the easel leg  26  provides support to prevent the keyboard system from tipping over backwards. 
     Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.