Abstract:
A method and apparatus are provided for improving the functionality of a remote input device while allowing for the input device to perform a number of roles. This is achieved by providing a detachable keyboard within a portable computer capable of functioning as both a hardwired, internal input device and as a remote, wireless input device. The input device of the invention is capable of being housed within a portable computer and performs as a typical on-board input device. In addition, the input device may be removed from the base of the computer and used as an internally-powered wireless control device. In the latter mode the communication between the input device and the computer takes place through a wireless link existing between the input device and the computer.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to portable computers and, more particularly, to data input devices for use with portable computers.  
         [0003]     2. Description of the Related Art  
         [0004]     Portable computers have proven to be popular in domestic, business and industrial environments due to the unrestricted freedom of movement they offer users. In addition, portable computers, also called laptop computers, have rapidly become a ubiquitous and useful tool in informational presentations, particularly multimedia presentations. Such multimedia presentations are most often performed through the use of a portable computer connected to a projector displaying an image on a screen. The computer controls the operation of the projector as well as the content on the screen.  
         [0005]     A typical portable computer is shown in  FIG. 6 . A portable computer  500  generally includes a display screen  502 , e.g. a liquid crystal display (“LCD”), which is attached by hinge mechanisms  503  to a base  504 . The base  504  includes a central processor unit (“CPU”), non-volatile and volatile memory, and a battery power supply (not shown). The base  504  also includes a keyboard  506 , and a mouse/trackball pointing unit  508  in the form of a small projection from keyboard  506  and mouse click switches  509 . A portable computer  500  may also have a number of optional components such as, for example, disk drive  510 , PMCIA card slot  512 , and speakers  514  within the base  504  or display screen  502 .  
         [0006]     To facilitate multimedia presentations, the portable computer  500  may also have a series of connectors  516  located on the outer side or back surface of the portable computer  500 . The portable computer  500  communicates with a presentation unit, e.g. a slide projector (not shown), through a hardwired connection from the presentation unit to a connector  516 . Alternatively, the communication may occur using wireless communication.  
         [0007]     Although the use of a portable computer  500  is more efficient than using a standard desktop computer in many cases, the user is still required to be physically proximate to the portable computer  500  to operate it. The ability to move around during a presentation or, at the least, choose your own seat is highly desirable. Prior solutions to this problem generally involve the purchase of separate computer peripherals capable of exercising remote control over the portable computer  500 .  
         [0008]     One solution has been the use of a mouse or similar peripheral device to control a presentation using a sufficiently long cord attached to the computer  500 . However, such peripherals are limited in their use since the user is relegated to only a rolling mouse or a “point and click” interface. Another solution has been the use of a second keyboard attached to the computer  500  through a hardwired connection to connector  516 . This can also be accomplished using a wireless connection, that is, the physical hard wire connection between a conventional keyboard and computer  500  is replaced by, for example, an infrared link. Control signals are thus transmitted from the keyboard to the computer  500  through an infrared link. The infrared link may be built into the computer  500  or, more commonly, is an additional peripheral which is purchased and then connected to a connector  516 .  
         [0009]     Currently, if the additional convenience of a remote input device is needed, a user must invest both time and money. This is often done at some sacrifice to usability and function due to the extra equipment and setup required to use such devices. Consequently, when such a system is used, additional equipment must be transported and reduced functionality is experienced in comparison to on-board input devices.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention provides a method and apparatus for improving the functionality of a remote input device while allowing for the input device to perform a number of roles. This is achieved by providing a detachable keyboard within a portable computer capable of functioning as both a hardwired, internal keyboard input device and as a remote, wireless keyboard input device. The keyboard input device of the invention is capable of being housed within a portable computer and performs as a typical hardwired on-board keyboard input device. In addition, the input device may be removed from the base of the computer and used as an internally-powered wireless keyboard input device. In the latter mode the communication between the keyboard input device and the computer takes place through a wireless link, possibly through infrared signals. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The foregoing and other advantages and features of the invention will become more apparent from the detailed description of embodiments given below with reference to the accompanying drawings, in which:  
         [0012]      FIG. 1  illustrates a portable computer system;  
         [0013]      FIG. 2  illustrates a block diagram of the portable computer system of  FIG. 1  in a wireless mode of operation;  
         [0014]      FIG. 3  is a block diagram of a keyboard constructed in accordance with the invention;  
         [0015]      FIGS. 4   a - 4   b  are block diagrams of infrared systems according to an embodiment of the invention;  
         [0016]      FIG. 5  is a flow chart of a method of operating the invention; and  
         [0017]      FIG. 6  illustrates a prior art portable computer. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0018]     An embodiment of the present invention will now be described with reference to  FIGS. 1-5 . Other embodiments may be realized and structural, electrical, or logical changes may be made to and equivalents used for the disclosed embodiment without departing from the spirit or scope of the present invention.  
         [0019]      FIG. 1  depicts a portable computer  10  constructed in accordance with an embodiment of the invention. The computer  10  includes a display screen  12 , e.g. a liquid crystal display (“LCD”), which is attached by hinge mechanisms  14  to a base  16 . The base  16  includes at least a central processor unit (“CPU”), non-volatile and volatile memory, and a battery power supply (not shown). The base  16  also includes a keyboard input device  18 . The illustrated keyboard input device  18  may operate over a hardwired connection (or another fixed signal interface) and a wireless link to the base  16  through wireless input/output transducers  20 .  FIG. 1  shows the computer  10  operating with keyboard input device  18  through a signal interface, e.g. in a hardwired mode, infrared (IR) mode, radio frequency (RF) mode, or other mode. The computer  10  may also have a number of optional conventional components such as, for example, disk drive  22 , speakers  24 , CD-ROM drive, DVD drive, etc.  
         [0020]      FIGS. 2 and 3  show input device  18  operating in a wireless mode after having been removed from the base  16  of computer  10 . As seen in  FIG. 2 , the computer  10  further comprises a hardwire connector  26 , electrical contacts  27 , a slot  28 , a recess  29  capable of holding keyboard input device  18 , and at least two retainer devices  30  (one of which is partially hidden in  FIG. 2  by the right sidewall of recess  29 ). Retainer devices  30  may be any mechanical biasing device which places pressure on the edges of input device  18  to prevent the movement of input device  18  in a vertical direction when it is seated in recess  29 . The retainer devices  30  may be spring-loaded ball bearings. The retainer devices  30  may also be fitted into concave grooves  31  in the sides of keyboard input device  18  when keyboard input device  18  is seated in recess  29 . The base  16  is also equipped with an eject mechanism  34  to aid in the removal of keyboard input device  18  from base  16 . The eject mechanism  34  is activated by trigger  32  to place an upward force sufficient to overcome the biasing force of the retainer devices  30  on the keyboard input device  18 , thus allowing for easy removal of keyboard input device  18  from recess  29 .  
         [0021]     The keyboard input device  18  comprises a wireless keyboard having a plurality of keys  36 , a hardwire connector  38  which engages with connector  26  when the keyboard input device  18  is seated in recess  29 , at least one removable battery  39 , and a tab  40  which is insertable in slot  28  to help hold the keyboard input device  18  in place in recess  29 . Keyboard input device  18  preferably has an upper surface  19 , a lower surface  21 , and four sides  23  perpendicular to the upper and lower surfaces  19 ,  21  and at least one infrared input/output transducer  42  provided at one or more locations on at least two sides  23  of keyboard input device  18 , as shown in  FIGS. 2 and 3 . Additionally, the keyboard input device  18  may be equipped with a pointing device  44  and at least two click switches  45  for enabling the usual “mouse click” inputs. Internally the input device  18  is equipped with a microprocessor unit (MPU) (not shown) to control the functions of the keyboard input device  18 . Pointing device  44  and click switches  45  perform the function of a computer mouse and may be provided in the form of a track ball apparatus, a touch pad apparatus, or other form of pointing device known in the art.  
         [0022]     Hardwire connectors  26  and  38  are constructed to mate so that when keyboard input device  18  is operating in a hardwired mode the connectors  26  and  38  interlock and electronically couple to allow signals to pass between the keyboard input device  18  and the base  16 . Hardwire connectors  26  and  38  may be a male/female pin-type connector pair where either the connector  26  is male and the connector  38  is female, or vice versa. Similarly, slot  28  and tab  40  are designed to engage and mate with one another to assist in the securing of keyboard input device  18  within base  16 . Slot  28  extends from the back wall of recess  29  toward the outer surface of base  16  by a distance equal to that of the length of tab  40 . Eject mechanism  34  may be a physically actuated device responsive to a force applied to trigger  32 . Eject mechanism  34  may be constructed as a simple lever device wherein command pressure on trigger  32  forces eject mechanism  34  to project up from the bottom of recess  29 , or as an electrically actuated solenoid device, depending upon the space and power requirements of the computer  10 .  
         [0023]     Power to the keyboard input device  18  is supplied through a direct connection to the base  16  or through a battery  39  depending upon the communication state of the computer  10 . Removable battery  39  is located within keyboard input device  18  in slot or recess  41 . In a hardwired communication state where the input device  18  is secured within recess  29 , power is supplied to the input device  18  through a hardwired connection to base  16 . This hardwired connection may be incorporated into connectors  26  and  38  or may be accomplished through the mating of electrical contacts  27  and battery  39 .  
         [0024]     Battery  39  may be a rechargeable battery pack, e.g. a metal hydride or lithium ion battery. Alternatively, keyboard input device  18  includes alternating current (AC) power input  64  as shown in  FIG. 3 . AC power input  64  is capable of receiving power through an AC power adapter cord  66 . This embodiment may be desirable to decrease reliance on battery  39  when keyboard input device  18  is operating remotely. The connection between electrical contacts  27  and the battery  39  is also active when input unit  18  is secured in base  16  in order to charge battery  39 . When the input device  18  is removed from the base  16  and is communicating in a wireless state, power is supplied to input device  18  through battery  39 .  
         [0025]     For establishing communications between the base  16  and the input device  18 , a plurality of wireless transducers  20  and  42  are provided on the base  16  and keyboard input device  18 , respectively. The base  16  may be equipped with at least three transducers  20  on at least three different edges of the base  16 . Similarly, there may be at least three transducers  42  located on three different edges of the input unit  18 . Such an arrangement will ensure reliable communication between the base  16  and the input device  18 , especially in cases where no two transducers  20 ,  42  are perfectly sight-aligned. The present invention may employ an infrared or radio frequency (RF) communication link between transducers  20  and  42 . Infrared communication links are known in the art, such as the one described in U.S. Pat. No. 4,628,541 which is incorporated herein by reference.  
         [0026]     Infrared wireless communication is conducted between keyboard input device  18  and base  16  through the transmission and reception of signals between transducer  42  and transducer  20 , as shown in  FIGS. 4   a  and  4   b . Each one of the transducers  42 ,  20  may include respective transmitters  50 ,  52 , possibly light emitting diodes (LED) operating in the infrared range, LED drivers  54 ,  56  to drive LEDs  50 ,  52  and sensors  51 ,  53  to sense incoming signals. The drivers  54 ,  56  are controlled by processors MPU  58  and CPU  60  which are the processing units respectively contained within the keyboard input device  18  and base  16 , as described above. Sensors  51 ,  53  may be sensors capable of receiving light having a wavelength in the infrared region and converting this received light into electric signals.  
         [0027]     Since the keyboard input device  18  does not generally require any outside data to be operational, transducer  42  may be solely a transmitter having only driver  54  and LED  50  and transducer  20  may be solely a receiver having only sensor  53 . Such an arrangement would be simple and cost-effective compared to a bi-directional infrared transmission system. However, either system may be used in the invention.  
         [0028]     To prevent confusion with other infrared or wireless devices which may be in nearby operation, the present invention may attach a unique identification (ID) code to outgoing infrared signals. In use, the infrared transducer  42  transmits data signals originating from the keys  36 , pointing device  44 , or click switches  45  with an accompanying ID code. The combined signal is transmitted by transducer  42  through a series of light pulses from LED  50 . The transducer  20  of the base  16  receives the signal using sensor  53  and transmits the combined signal to CPU  60 . CPU  60  isolates the ID code and compares the received ID code with a reference ID code. If the two ID codes are identical, CPU  60  to accepts that the data signal originated from keyboard input device  18  and not from another device using infrared transmission, e.g. a television remote control.  
         [0029]     In operation, the computer  10  is capable of operating in at least installed and remote communication modes. In one embodiment of the installed mode, the keyboard input device  18  is secured within depression  29  of the base  16 . Tab  40  is within slot  28 , battery  39  is electrically connected to electrical contacts  27 , hardwire connector  26  is coupled to hardwire connector  38 , and eject mechanism  34  is in a pre-eject state. In addition, retainer devices  30  are engaged to provide pressure on the edges of keyboard input device  18 , further securing it from movement within recess  29 . In the installed mode, the input device  18  may be in communication with the CPU of base  16  through a suitable signal interface such as hardwire connectors  38 ,  26  and powered by the power source of base  16 . Although wireless communication is possible in this state if an additional transducer  20  were to be placed inside the recess  29 , hardwired communication may be desirable in some circumstances because it consumes less power.  
         [0030]     A remote communication mode may be started in a number of ways. The computer  10  may enter the remote communication mode upon the activation of eject mechanism  34  using trigger  32  as shown in the flow chart of  FIG. 5 . This may be accomplished by the constant monitoring of hardwire connector  38  by the MPU  58  of input device  18 , as in process segment S 1 . Upon detection of a break in the electrical connection with hardwire connector  26 , the MPU  58  of the keyboard input device  18  begins operating in remote mode, as in process segment S 2 . Another method for determining whether a hardwired connection exists is through an electronic signal sent to the keyboard input device  18  and base  16 , either through a software-based command or a specialized key  36  or other button located on the base  16  or keyboard input device  18 .  
         [0031]     Once a remote communication mode is entered, the keyboard input device  18  may be used remotely from the base  16  at a distance and location defined by the strength and location of the transducers  42 . If a key  36  is depressed or the pointing device  44  is used, as in process segment S 3 , the MPU  58  of the keyboard input device  18  assigns a key code to the depressed key according to its position on the keyboard input device  18 , as in process segment S 4 . The MPU  58  of input device  18  then combines the key code with the ID code unique to computer  10 , as in process segment S 5 . The transducer  42 , through the infrared driver  54  and LED  50 , emits the key code and ID code signal, as in process segment S 6 .  
         [0032]     Sensors  53  of transducers  20  receive the infrared signals from transducer  42  and output a corresponding electrical signal to the CPU  60  of base  16 , as in process segment S 7 . Next the CPU  60  determines if the received ID code matches the predetermined ID code corresponding to keyboard input device  18 , as in process segment S 8 . If the ID code of the received signal does not match the predetermined ID code, the received signal is rejected and the base  16  continues to monitor for signals, as in process segment S 7 . If the ID code of the received signal matches the predetermined ID code, the received signal is accepted by the CPU  60  of the base  16  as a direction from keyboard input device  18 , as in process segment S 9 . In the embodiment in which the transducers  20  and  42  are capable of communication in a bi-directional mode, transmission from the base  16  and reception by the keyboard input device  18  is performed in a similar manner.  
         [0033]     If the hardwired connection between connectors  26  and  38  exists, communication between the base  16  and the keyboard input device  18  is conducted by the transfer of electrical signals through connectors  26  and  38 , as in process segment S 10 .  
         [0034]     It should be readily apparent that although only one method of transmitting wireless signals using an infrared system has been described for purposes of simplicity, any infrared, RF, or other wireless form of communication may be used. For example, transmitter  50  and sensor  53  may be an RF transmitter and an RF sensoring device. In addition, although the removable input device has been disclosed as a removable keyboard input device  18 , the invention can also be applied to other removable input devices of a portable computer, such as a removable mouse. Furthermore, the invention may be successfully implemented within computer environments, not solely portable computers. For example, the present invention may be employed in special use computers such as personal digital assistants.  
         [0035]     While the invention has been described in detail in connection with embodiments known at the time, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.