Abstract:
A communication device comprising a keymat, a cover, and a substrate comprising a plurality of key switches is disclosed. The keymat comprises a plurality of lips located at the edges of the keymat. The cover comprises a plurality of indentations configured to receive the plurality of lips. The indentations are located at the edges of a recess for removably mounting the keymat.

Description:
FIELD OF INVENTION  
       [0001]     The present invention relates to a communication device with an on a cover exteriorly attachable keymat, a cover for an exteriorly attachable keymat, and an exteriorly attachable keymat.  
       BACKGROUND OF INVENTION  
       [0002]     It has become desirable for users of radiotelephones to replace a cover of the radiotelephone easily without requiring any special training or tools. Telephone handsets with exchangeable covers are known, e.g. from EP 1028574 A2. EP 1028574 A2 discloses a radio telephone comprising a front and a back cover. The radio telephone further comprises an inner housing retaining electronic components of the radiotelephone.  
         [0003]      FIG. 1  shows a prior art radiotelephone  1  with a front cover  2 , a back cover  3 , an inner housing  4 , and a keymat  5 . To assemble the radiotelephone  1 , the front and back covers  2 ,  3  are attached to mutual sides of the inner housing  4 . The keymat  5  is sandwiched between the front cover  2  and the inner housing  4  such that keys  6  of the keymat  5  extend through holes  7  in the front cover  2  and, when a key is pressed, actuate key switches (not shown) on the inner housing  4 . The main purpose of the keymat is to act as an interface between the user and the functions of the radiotelephone.  
         [0004]     A problem with known technology is that a change of keymat require that the front cover is removed from the internal housing.  
         [0005]     Another problem is that the front cover limits the freedom to design the keys of the keymat, since the keys have to fit the holes of the front cover.  
         [0006]     U.S. 2003/0201983 discloses a keymat for use with a mobile station. The keymat includes a web for interconnecting a plurality of keys. The keymat is attached externally on a cover of the mobile station to permit a user to exchange the keymat for another. A plurality of key pins extends through openings in the cover of the mobile station. The keymat has retaining means for removably retaining the keymat to the mobile station. The retaining means are either key pins integrally formed with the keymat and extending inwardly through openings in the cover of the mobile station and provided with extensions on the key pins to engage the interior surface of the cover, or recesses in the keymat for receiving the key pins, or a slide plate disposed inward of the cover for engaging a keymat fixedly attached to a plurality of key pins that forms a recess for engaging the slide plate.  
         [0007]     A problem with this solution is that the edges of the keymat is unprotected and not tightly attached to the cover, and may cause that the keymat is ripped off the cover during every day use, such as keeping the mobile station in a pocket or bag. Another problem with this solution is that attachment and removal are difficult. Further, a problem with this solution is that, when removing the keymat, the stress on the extensions for retaining the keymat many times will cause that the extensions are torn off, and it will not be possible to re-attach the keymat.  
       SUMMARY OF THE INVENTION  
       [0008]     An object of the present invention is to overcome at least a part of the above stated problems.  
         [0009]     The above object, together with numerous other objects, which will become evident from the detailed description below, is obtained according to a first aspect of the present invention by a communication device comprising a keymat, a cover, and a substrate comprising a plurality of key switches, wherein the keymat is exteriorly attachable on the cover, and keypins of said keymat extend through holes of said cover towards said plurality of key switches, wherein the keymat comprises a plurality of lips located at the edges of the keymat, and the cover comprises a plurality of indentations configured to receive the plurality of lips, wherein the indentations are located at the edges of a recess for removably mounting the keymat.  
         [0010]     The keymat may comprise one or more guiding pieces, and the cover may comprise one or more corresponding guiding recesses. The guiding pieces may be arranged in direct connection to one or more of the plurality of lips.  
         [0011]     The keymat may be provided with one or more guiding recesses, and the cover may be provided with one or more corresponding guide pieces. The guiding pieces may be one or more ribs extending to be received by the guide pieces.  
         [0012]     The above object, together with numerous other objects, which will become evident from the detailed description below, is obtained according to a second aspect of the present invention by a cover for a communication device comprising a recess for receiving a keymat comprising a plurality of lips, wherein the recess is provided with a plurality of indentations located at the edges of the recess for receiving the plurality of lips.  
         [0013]     The cover may further comprise one or more guiding recesses. The one or more guiding recesses may be arranged in direct connection to one or more of said plurality of indentations.  
         [0014]     The cover may further comprise one or more guiding pieces. The guiding pieces may be one or more ribs on a surface of the cover facing a place where a keymat is to be mounted.  
         [0015]     The above object, together with numerous other objects, which will become evident from the detailed description below, is obtained according to a third aspect of the present invention by a keymat for removable mounting on a cover of a communication device, comprising lips located at the edges of the keymat. The lips are configured to insert into indentations of said cover.  
         [0016]     The keymat may further comprise one or more guiding pieces. The guiding pieces may be arranged in direct connection to one or more of said plurality of lips.  
         [0017]     The keymat may further comprise one or more guiding recesses. Said one or more guiding recesses may be an incision in a surface that is to be in contact with a cover when mounted on the cover.  
         [0018]     The keymat may be moulded in one piece.  
         [0019]     A particular feature of the present invention relates to the possibility to mount, demount, and remount the keymat without any tools or training.  
         [0020]     A particular advantage of the present invention is easier mounting, demounting, and remounting of a keymat since the cover do not have to be removed. Further, an advantage of the invention is that the retaining of the keymat is improved, and the risk for unintentional removal of the keymat during wearing and using the communication device is decreased. Another advantage of the present invention is that a designer has more freedom in designing different keymats, and the user has more freedom in changing keymats. Another advantage of the present invention is a more attractive appearance, since the recess of the cover enables the keymat to be in level of the cover. Another advantage of the present invention is reduced costs since the exchangeable keymat can be moulded in one piece, and material can be saved. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  shows a telephone according to prior art.  
         [0022]      FIG. 2  shows a communication device according to the present invention.  
         [0023]      FIG. 3  shows an embodiment according to the present invention.  
         [0024]      FIG. 4   a  and  4   b  are views of a front cover with a mounted keymat seen from opposite sides, respectively.  
         [0025]      FIG. 5  shows a cross section view of an embodiment of the present invention.  
         [0026]      FIG. 6  shows a cross section view of an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0027]      FIG. 2  shows a communication device  100  which is provided with a plurality of parts, e.g. a processor (not shown), radio electronics (not shown), a substrate (not shown), a microphone  104 , a speaker  106 , a display  108  and a plurality of key switches (not shown). The communication device  100  is also provided with a front cover  102 , a back cover (not shown) and a keymat  110 .  
         [0028]      FIG. 3  shows a front cover  202  and a keymat  206  according to an embodiment of the present invention, wherein the front cover  202  is provided with a recess  204  to receive the keymat  206 . The keymat  206  is preferably made of rubber or any elastomer. The keymat  206  is provided with a plurality of lips  208 ,  210 ,  212 ,  214  that enables a removable mounting of the key mat  206  on the front cover  202 . The keymat  206  is mounted by bending the keymat  206  slightly and putting it into the recess  204 , and the elastic properties of the keymat  206  will force the lips into corresponding indentations of the front cover  202 . Similarly, the keymat  206  is demounted by bending the keymat  206  slightly and lifting it out of the recess  204 . The keymat  206  is also provided with a guide piece  216  that enables guiding the keymat  206  to a correct position at the front cover  202 . The guide piece  216  is received by a corresponding guide recess in the front cover  202 .  
         [0029]      FIG. 4   a  is a front view of a front cover  302  with a mounted keymat  304 . When the keymat  304  is mounted in the front cover  302 , the lips are not visible, and an attractive appearance is achieved. A designer now has the ability to design the keypad with the keys  306  of the keymat  304  more freely.  
         [0030]      FIG. 4   b  is a view of the front cover  302  with the mounted keymat  304  from the opposite side compared to  FIG. 4   a.  A plurality of pressure transmitters  308 , one for each key  306  of the keymat  304 , protrudes through a plurality of holes  310  in the front cover  302 , thereby enabling actuation of a plurality of key switches of a communication device. The pressure transmitters  308  are bosses formed when moulding the keymat  304 .  
         [0031]     Guide pieces  312 ,  314  guide the keymat  304  to a correct position by fitting into recesses  316 ,  318  of the front cover  302 . The guide pieces  312 ,  314  are flanges extending from the surface of the keymat  304  facing the cover  302 , through the recesses  316 ,  318 , when the keymat  304  is attached to the cover  302 . Lips  320 ,  322 ,  324 ,  326 ,  328 ,  330 ,  332  of the keymat  304  insert into indentations of the front cover  302  to hold the keymat  304  without adhesive, glue, tape, or other mounting means. Preferably, the guide pieces  312 ,  314  are arranged in direct contact with some of the snap connectors  320 ,  322 .  
         [0032]      FIG. 5  shows a cross section view of a front cover  402  and a keymat  404  according to an embodiment of the present invention. The front cover  402  is shown with the mounted keymat  404 . The front cover  402  is provided with a guide piece  406 , that is received by a guiding recess  408  in the keymat  404  to ensure a correct positioning of the keymat  404 . The guide piece  406  is a rib on the surface facing the keymat  404  and the guide recess  408  is an incision in the surface facing the cover  402 . The keymat is provided with lips  410 ,  412  that are received by indentations  414 ,  416  in the front cover  402  to hold the keymat  404  without adhesive, glue, tape, or other mounting means.  
         [0033]      FIG. 6  shows a cross section view of a front cover  502  and a keymat  504  according to an embodiment of the present invention. The front cover  502  is shown with the mounted keymat  504 . The keymat is provided with lips  506 ,  508  that are received by indentations  510 ,  512  in the front cover  502  to hold the keymat  504  without adhesive, glue, tape, or other mounting means. The front cover  502  is further provided with locking parts  514 ,  516  that forces the lips  506 ,  508  of the keymat  504  into the indentations  510 ,  512  of the front cover  502  to improve gripping pressure.  
         [0034]     The front cover  502  is provided with a plurality of holes  518 ,  520 ,  522  to enable pressure transmitters  524 ,  526 ,  528  to protrude through the front cover  502  to reach key switches located on a substrate of the communication device (not shown).  
         [0035]     The keymat  504  is provided with a plurality of keys  530 ,  532 ,  534 . When one of the keys  530 ,  532 ,  534  is pressed, the corresponding pressure transmitter  524 ,  526 ,  528  displaces and actuates the corresponding key switch (not shown).  
         [0036]     In the above presented embodiments of the present invention, a keymat is mounted on a front cover. It is the most common design of a communication device to locate a keypad on the front of the communication device. However, a keypad can be located on a back cover, on a cover of a tiltable and/or swivable part where the terms “front” and “back” are not applicable, or anywhere on a cover of the communication device. Therefore, the invention is applicable on any cover used for a communication device.