Abstract:
There is disclosed a keypad apparatus and a method for determining the status of a keypad apparatus. In one embodiment, the keypad apparatus includes a keypad having a plurality of keys and a keypad matrix associated with the keypad and having a switch. The keypad apparatus also includes a cover moveable between an open and a closed position. The keypad apparatus still further includes a means for engaging that cooperates with and allows the switch to provide a status indicating a position of the cover.

Description:
CROSS-REFERENCE TO FOREIGN APPLICATION  
         [0001]    This application claims the benefit of EP Patent Application No. 02251790.8 entitled “Flip-Cover Sensor for Keypad,” to David J. Bennetts, et al., filed on Mar. 13,  2002 , which is incorporated herein by reference.  
         FIELD OF THE INVENTION  
         [0002]    The present invention is directed, in general, to a keypad apparatus having a keypad housing with a flip-cover and, more specifically, to a mobile telephone or a personal digit assistant (PDA) having a flip-cover.  
         BACKGROUND OF THE INVENTION  
         [0003]    While there may be a general desire to minimize the size of mobile telephones, there is a physical restriction in reducing the size due to a need for the ear piece to be positioned proximate the user&#39;s ear at the same time as the mouth piece is positioned proximate the user&#39;s mouth. This theoretically dictates that the length of the mobile telephone must be a certain minimum size.  
           [0004]    It has been recognized that the position of the ear piece and the mouth piece is only critical when the mobile telephone is in use. Based on this, mobile telephones have been developed with a ‘flip-cover.’ When the mobile telephone is not in use, the flip-cover folds or slides back onto a keypad housing of the mobile telephone and, therefore, does not increase the overall size of the mobile telephone. When a call is to be made or received, the flip-cover is opened such that the length of the mobile telephone becomes longer and the mouthpiece for the user is more practically positioned.  
           [0005]    Typically, mobile telephone designs having a flip-cover include a means such that the state of the flip-cover, either open or closed, is detected. The detection of the flip-cover state, for example, may be used for answering a call (on opening the flip-cover) and terminating a call (on closing the flip-cover).  
           [0006]    Presently, a sensor switch, such as a micro-switch, may be recessed within the surface of the keypad housing to engage with a switch activator on the cover. The switch activator is usually a small protrusion that extends into a recess of a surface of the mobile telephone when the flip-cover is closed thereby engaging, or activating, the sensor switch. This sensor switch provides an input signal to a general-purpose input/output (GPIO) pin of a micro-controller within the mobile telephone. Thus, the micro-controller within the mobile telephone receives a dedicated signal indicating whether the flip-cover is open or closed.  
           [0007]    One disadvantage with this present detection of the flip-cover state is that the provision of extra pins on the micro-controller integrated circuit package increases the cost of the integrated circuit. Therefore, the provision of a dedicated GPIO pin to the micro-controller for the purpose of detecting the status of the flip-cover increases the cost of the micro-controller integrated circuit. Alternatively, using a spare GPIO pin for this purpose prevents it from being used for another purpose.  
           [0008]    One proposal for detecting the flip-cover state includes using a switch matrix associated with a keypad of the mobile telephone. A switch of the switch matrix may receive a signal which in an alternate detection process would have been provided to the GPIO pin of the micro-controller. In such a proposal, when the particular switch of the matrix is not pressed, a signal is sent to a keypad controller to indicate that the flip cover is open. The disadvantage with this proposal, however, is that an entire row of the keypad switch matrix is inoperable while the flip cover is open since one of the switches in that row of the switch matrix will be constantly activated. Hence that row is not usable. The proposal, therefore, is not practical since it is unlikely that an entire row of the switch matrix may be unused and still provide a sufficient number of keys for normal operation of the mobile telephone.  
           [0009]    Accordingly, what is needed in the art is an improved arrangement for detecting the status of a flip-cover associated with a keypad apparatus, such as a mobile phone, that overcomes the deficiencies in the prior art.  
         SUMMARY OF THE INVENTION  
         [0010]    To address the above-discussed deficiencies of the prior art, the present invention provides a keypad apparatus. In one embodiment, the keypad apparatus (e.g., a mobile phone) includes a keypad having a plurality of keys and a keypad matrix associated with the keypad and having a switch. The keypad apparatus also includes a cover moveable between an open and a closed position. The keypad apparatus still further includes a means for engaging that cooperates with and allows the switch to provide a status indicating a position of the cover. When the cover is in the closed position, the status of the switch corresponds to a key pressed state.  
           [0011]    In a preferred embodiment, the means for engaging may include a switch actuator. The switch actuator may be a protrusion on the surface of the cover that engages the switch when the cover is in the closed position. The switch may be recessed in a housing of the keypad.  
           [0012]    In another embodiment, at least one of the plurality of keys is preferably uncovered with the cover in the closed position. In yet another embodiment, with the cover in the open position, the status of the switch preferably corresponds to a key unpressed state.  
           [0013]    According to the present invention, there is also provided a method for determining the status of a keypad apparatus. In one embodiment, providing a keypad having a plurality of keys and a keypad matrix associated with the keypad and having a switch. The method also includes allowing a cover to move between an open and a closed position and selectively engaging the switch to provide a status indicating a position of the cover. When the cover is in the closed position, the status indicates that the keypad apparatus is in a key pressed state.  
           [0014]    The method preferably includes covering at least one of the plurality of keys with the cover in the closed position. The method also preferably includes uncovering at least one of the plurality of keys with the cover in the open position. With the cover in the open position, the status of the switch preferably corresponds to a key unpressed state.  
           [0015]    The foregoing has outlined preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:  
         [0017]    [0017]FIG. 1 illustrates a diagram of an embodiment of a mobile telephone constructed in accordance with the principles of the present invention;  
         [0018]    [0018]FIG. 2 illustrates a diagram of a view through cross-section A-A of FIG. 1;  
         [0019]    [0019]FIG. 3 illustrates a block diagram of an embodiment of an implementation of a matrix array for the mobile telephone of FIG. 1 constructed in accordance with the principles of the present invention; and  
         [0020]    [0020]FIG. 4 illustrates a block diagram of an embodiment of the mapping of external inputs of the mobile telephone to the keypad matrix of FIG. 3, constructed in accordance with the principles of the present invention.  
     
    
     DESCRIPTION OF PREFERRED EMBODIMENT  
       [0021]    The present invention is described herein with reference to a particular non-limiting example. A person skilled in the art will appreciate that the invention is more generally applicable. In particular, the present invention is described in relation to a mobile telephone. However, the present invention may be more broadly applied to any keypad apparatus and, particularly, to a housing in which a keypad is situated.  
         [0022]    Referring initially to FIG. 1, there is illustrated a mobile telephone, generally designated  10 , in which the invention may be advantageously utilized. The mobile telephone  10  includes a main housing  14  and a cover  12 . The main housing  14  includes a screen  20 , and a top surface of the housing  30  within which is provided a plurality of keys  26  collectively forming a keypad. The cover  12  is attached to the main housing  14  by means of a hinge  24  at the junction of the top surface of the housing  30  and a side surface of the housing  28 . The cover  12  is movable with respect to the main housing  14  by means of the hinge  24 , such that in a closed position the cover  12  rests on a portion of the main housing  14 . In an open position, the cover  12  extends beyond the main housing  14 , such that in the illustrated embodiment the top surface of the housing  30  upon which the keypad is provided is uncovered. In moving from the closed to open position, the cover  12  moves through approximately 180 degrees. The cover  12  may be a typical flip-cover that is well-known in the art.  
         [0023]    As can be seen from FIG. 1, the top surface of the housing  30  may include an opening  16 . Referring to FIG. 2, which shows a cross-section through A-A of FIG. 1, the opening  16  is shown to extend into the main housing  14 . FIG. 2 also illustrates that the cover  12  includes a protrusion  18  which extends from the surface thereof. The protrusion  18  is shaped such that it engages the opening  16 . Thus with the cover  12  closed, the protrusion  18  extends into the opening  16 .  
         [0024]    As shown in FIG. 2, in the main housing  14  there is provided a switch  17 . The protrusion  18  is adapted such that with the cover  12  closed, the protrusion  18  engages the switch  17  to switch or change a state of the switch  17 . Thus, if the switch  17  is normally open, the protrusion  18  closes the switch  17  on closing the cover  12 . If the switch  17  is normally closed, the protrusion  18  opens the switch  17  on closing the cover  12 . The main housing  14 , therefore, is provided with a means to engage to indicate the status of the cover  12  by cooperatively engaging with the cover  12 .  
         [0025]    In accordance with the present invention, the switch  17  comprises a switch of a keypad matrix array, and provides an input signal to a handset micro-controller of the mobile telephone  10  in a similar manner as the plurality of keys  26  of FIG. 1 may provide an input signal. This is further discussed with reference to FIG. 1.  
         [0026]    Referring to FIG. 3, there is illustrated an embodiment of a matrix arrangement, generally designated  33 , for processing inputs provided by the plurality of keys  26 . The matrix arrangement  33  will be familiar to one skilled in the art, and only the necessary details are discussed herein to understand the prevent invention.  
         [0027]    The matrix arrangement  33  is a 5×5 matrix, which allows for 25 keys to be connected thereto. The matrix arrangement  33  comprises a set of 25 switches  34   a - 42   e.  Each switch is associated with a key. Pressing a key activates the associated switch. The switches  34   a - 42   e  are arranged in five rows  34 ,  36 ,  38 ,  40 ,  42 . Each row has five columns a, b, c, d, e. Each of the switches  34   a - 42   e  provides an input on a column line to a matrix controller  32 , which may be, for example, a micro-controller of the mobile telephone  10 . The switches  34   a - 34   e  provide an input to the matrix controller  32  on line  44 , the switches  36   a - 36   e  provide an input to the matrix controller  32  on line  46 , the switches  38   a - 38   e  provide an input to the matrix controller  32  on line  48 , the switches  40   a - 40   e  provide an input to the matrix controller  32  on line  50 , and the switches  42   a - 42   e  provide an input to the matrix controller  32  on line  52 . The matrix controller  32  generates an output to the switches in row a on line  54 , to the switches in row b on line  56 , to the switches in row c on line  58 , to the switches in row d on line  60 , and to the switches in row e on line  62 .  
         [0028]    As is known in the art, responsive to depression of one of the plurality of keys  26 , the associated switch of the matrix arrangement  33  is closed. For the purposes of an illustrative example, assume that the switch  38   c  is closed. Responsive thereto, a signal is generated on line  48  to the matrix controller  32 . In order to determine which of the switches in the row  38  has generated such a signal, the matrix controller  32  sequentially applies a signal on column lines  54 ,  56 ,  58 ,  60 ,  62  and at the same time continues to monitor row line  48 . As the switch  38   c  is closed, the matrix controller  32  sees a change in the signal on line  48  when a signal is applied to line  58 , and the matrix controller  32  thereby identifies which switch has been closed. One skilled in the art will understand the operation of the matrix arrangement  33 .  
         [0029]    In a typical application, the matrix arrangement  33  may have redundant switches. That is, the matrix arrangement  33  may have more switches than are needed to provide for the plurality of keys  26  of the mobile telephone  10 . Spare matrix switches, therefore, may be available. For example, the mobile telephone  10  may have a total of 22 keys resulting in three redundant or spare switches in the matrix arrangement  33 . One skilled in the art will understand that in view of the matrix arrangement  33 , the spare switches may be provided even though they are redundant.  
         [0030]    In accordance with the preferred embodiment of the present invention, one of the spare switches of the matrix arrangement  33  may be utilized as the switch  17  of FIG. 2 for detecting the status of the cover  12 . For example, assuming switches  42   c,    42   d,    42   e  are spare switches, then the switch  42   e  may be allocated for use as the switch  17  of FIG. 2. When the switch  42   e  is closed (or opened depending on the configuration of the switches), the closing of the cover  12  is detected directly by the matrix controller  32  using conventional inputs and outputs as shown in FIG. 3. Similarly the opening of the cover  12  from a closed position may also be detected. Thus the matrix controller  32  does not require any additional input/output pins in order to detect the status of the cover  12 .  
         [0031]    In FIGS. 1 and 2, the cover  12  covers all of the plurality of keys  26  while in other embodiments this may not be the case. The cover  12 , for example, may cover a selected number of the plurality of keys  26  (e.g., the volume keys may be uncovered). The cover  12  may also cover none of the plurality of keys  26  since the purpose of the cover  12  may be to reduce the overall size of the mobile telephone  10  when not receiving or making a telephone call. For example, there may be a desired application where the cover  12  does not cover any of the plurality of keys  26  when a user enters numbers into memory of the mobile telephone  10  which does not require setting up an active call. In these instances, the location of the opening  16  will be positioned appropriately in order to ensure appropriate engagement with the cover  12  on closing.  
         [0032]    Turning now to FIG. 4, illustrated is a block diagram of an embodiment of a mapping of external inputs of the mobile telephone  10 . FIG. 4 illustrates some of the plurality of keys  26  mapped to various switches of the matrix arrangement  33  of FIG. 3. In addition, FIG. 4 illustrates the protrusion  18  mapped to the switch  42   e  of the matrix arrangement  33 .  
         [0033]    According to FIG. 4, the mobile telephone  10  may operate as follows. When the cover  12  is open, then the switch  42   e  is not engaged by the protrusion  18  and the switch  42   e  is an “unpressed key” from the perspective of the matrix controller  32 . When the cover  12  is closed, then the switch  42   e  is engaged by the protrusion  18  and the switch  42   e  is a “pressed key” from the perspective of the matrix controller  32 .  
         [0034]    The status of the cover  12 , therefore, may be incorporated as part of the matrix arrangement  33 . The ‘open’ status of the cover  12  may be determined by a “key unpressed” state whereas the ‘closed’ status of the cover  10  may be determined by a “key pressed” state. The “key pressed” state means that the row of the switch matrix is unusable. However, this does not matter if all the keys of that row are covered by the closed cover  12  or if any other switches of the matrix arrangement  33  associated with that row are unused. The number and identifications of the plurality of keys  26  covered on detection of closure of the cover  12  may be determined by the matrix controller  32  of the mobile telephone  10  and may depend upon a physical design of the mobile telephone  10 .  
         [0035]    Although the invention has been described herein with reference to a mobile telephone having a ‘flip’ cover, the applicability of the present invention is not so limited. The invention may apply equally advantageously, for example, in a keypad apparatus having a keypad with a slide cover. The opening and closing of the slide cover may be detected in the same way as described above regarding the cover  12  of the mobile telephone  10 . The present invention, therefore, broadly applies to any device having a keypad with a moveable cover.  
         [0036]    Further, inputs to a matrix array of switches to determine the status of a cover may be implemented by alternative means. For example, in an alternative implementation of the present invention, the protrusion  18  on the cover  12  may engage with an actual dedicated key of the plurality of keys  26  rather than the opening  16 . In such an alternative implementation, there would preferably need to be a spare key available on the keypad for such use.  
         [0037]    The invention has been described herein with reference to particular preferred embodiments. One skilled in the art will appreciate the broader applicability of the present invention, the scope of which is limited only by the attached claims.