Patent Publication Number: US-7898440-B2

Title: Keyboard for a handheld electronic device

Description:
FIELD OF THE INVENTION 
     The invention relates to a keyboard, and more particularly to a keyboard for use in a handheld electronic device. 
     BACKGROUND OF THE INVENTION 
     Due to rapid advance of electronic technology, the handheld electronic devices, such as mobile phones or personal digital assistants (PDAs), of nowadays have multipurpose functions, like sending short messages and e-mails, playing music, taking picture and making simple calculation. The handheld electronic device therefore becomes an indispensable part in our daily life. In order to provide the aforementioned multi functions, the handheld electronic device is usually provided with a keyboard for input of commands of signals, more specifically letters for inputting of words during sending of a short message. 
     In order to enable the user for inputting the words, the handheld electronic device is generally provided with a keyboard having a plurality sets of keys. The user may press these sets of keys when he or she wishes to input the words. Some of the handheld electronic devices (like PDAs) are provided with standard keyboards, generally known as QWERTY board like keyboard of a personal computer. The QWERTY board has a plurality of keys, each corresponding to one “Letter”. Under this condition, the user can quickly input the words, by typing the keys continuously since each of the keys corresponds to a letter or a phonetic alphabet. 
     It is noted that the QWERTY board has a relatively large dimension since there are more than 26 keys. As a result, the handheld electronic device must also possess a bulky size in order to accommodate the sets of keys. The handheld electronic device thus cannot be constructed in compact size, thereby inconveniencing the user whenever he wants to take along the device with him. The size of the handheld electronic can be reduced to facilitate the user to carry along with him. The size reduction of the device may lead to some difficulties, such as the keys are too small to operate or the printed symbol on the key is not easily visible. 
     In some of the handheld electronic devices, the QWERTY board is substituted by a touch screen or touch interface in order to minimize the dimension of the device so as to eliminate the aforementioned drawbacks. The user can directly press the touch screen by finger or stylus whenever he wishes to input a signal. Input of words or signals by means of finger or stylus is slow when compared with the conventional typing habit of the user. In addition, the image or letter in the touch screen is not easily visible due to over brightness of the ambient light (the sun), thereby causing inconvenience to operate the touch screen. 
     In order to eliminate the aforementioned drawbacks, another handheld electronic device has been proposed such that the latter includes a plurality of condensed keys, i.e. each corresponds to several letters or numerals. For example, when sending a short message, the user can press the key having the numeral 3 for 6 times in case he wishes to input the letter “f”. When each of the condensed keys is thus arranged, the dimension the handheld electronic device is greatly reduced to facilitate the user to carry along with him. 
     Since it requires the user to press a condensed key several times in order to result in a specific letter, the condensed key lacks the advantage offered by the QWERTY keyboard. Sometimes, the user may accidentally over press the condensed key, thereby resulting in an undesired letter. In other words, several errors may occur and it causes time waste to use the condensed keys for input of words. 
     SUMMARY OF THE INVENTION 
     Therefore, it is the object of the present invention to provide a keyboard for use in a handheld electronic device. The keyboard is free from the difficulties encountered during use of the conventional keyboard, thereby simplifying the input operation. 
     The other object of the present invention is to provide a keyboard having fewer keys without reducing the capability thereof, thereby reducing the dimension of the keyboard. 
     According to the present invention, a keyboard for a handheld electronic device is provided. The keyboard includes a plurality of input keys; a front panel adapted to be mounted on an outer surface of the handheld electronic device, the front panel being formed with a mounting hole for receiving a respective one of the input keys; a sliding and pressing mechanism disposed below the front panel to permit sliding movement of the respective input key in vertical and horizontal directions of the mounting hole so as to result in collision of the respective input key against a circuit within the handheld electronic device; and a spring unit disposed below the front panel for providing a restoration force that permits the respective input key to retrieve its initial position upon removal of an applied force for moving the respective input key along the vertical and horizontal directions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Other features and advantages of this invention will become more apparent in the following detailed description of the preferred embodiments of this invention, with reference to the accompanying drawings, in which: 
         FIG. 1  is a handheld electronic device provided by the first preferred embodiment of a keyboard of the present invention; 
         FIG. 2  is an exploded view of the first preferred embodiment of the keyboard of the present invention; and 
         FIG. 3  is a partly sectional view of the second preferred embodiment of the keyboard of the present invention taken along the line A-B in  FIG. 1 . 
     
    
    
     DETAILED DESCCRIPTIONS OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a perspective view of the first embodiment of a handheld electronic device  100  of the present invention. The handheld electronic device  100  includes a keyboard  110  consisting of a front panel  120  and a plurality of input keys  111 . The keyboard  110  can be a QWERTY keyboard. 
     Each of the input keys  111  is slidable or pressible on the front panel  120  in the horizontal direction or the vertical direction (i.e. downward with respect to the front panel  120 ) similar to the conventional keyboard. The user can slide a respective input key  111  in the horizontal direction in order to input a letter. Alternately, the user can press the respective input key  111  downward with respect to the front panel  120  in the vertical direction in order to input the letter. 
     In this embodiment, each of the input keys  111  of the keyboard  110  is capable of inputting three different sets of letters including the first-set letter, the second-set letter and the third-set letter. To be more specific, when the input key  111  is moved forward in the horizontal direction, the first-set letter is generated. When the input key  111  is moved rearward in the horizontal direction, the second-set letter is generated. When the input key  111  is pressed downward with respect to the front panel  120  in the vertical direction, the third-set letter is generated. 
     Furthermore, the forward, rearward and downward movement of the input key  111  with respect to the front panel  120  along the horizontal and vertical directions can be arranged to repeat for several times. If such arranged, each of the input keys  111  is capable of inputting more than three different sets of letters. 
     Referring to  FIG. 1 , where the first-set letter is [W], the second-set letter is [Z], and the third-set letter is [S], in case the input key  111  printed with [S] is moved forward in the horizontal direction so as to collide with the input key  111  printed with [W], the letter [W] is generated. When the input key  111  printed with [S] is moved rearward in the horizontal direction so as to collide with the input key  111  printed with [Z], the letter [Z] is generated. In the same manner, when the input key  111  printed with [S] is pressed downward with respect to the front panel  120  in the vertical direction, the letter [S] is generated. It can be arranged that a symbol [−] is generated in case the input key  111  printed with [S] is pressed downward twice with respect to the front panel in the vertical direction. Of course, the input keys  111  can be switched into other mode such that sliding movement of the input keys  111  in the horizontal direction and pressing action of the input keys  111  in the vertical direction may result in phonetic alphabet or Arabic numerals. 
     In this embodiment, a sliding and pressing mechanism  210  is employed in the keyboard  110  of the present invention so as to permit movement of the input keys  111  the horizontal or vertical direction. Furthermore, spring unit is also used to permit the input keys  111  to retrieve its initial position upon removal of an applied force. 
     Referring to  FIG. 2 , the front panel  120  is mounted on an outer surface of the handheld electronic device  100 . The front panel  120  is formed with a mounting hole or slot  121  for receiving a respective one of the input keys  111 . As a matter of fact, two parallel long sides and two parallel short sides interconnecting to the long sides define the mounting hole  121 . The input keys  111  are arranged along the longitudinal length of the mounting hole  121  in the front panel  120 . Of course, the front panel  120  can be formed with a plurality of mounting holes  121 , each receiving a respective input key  111 . 
     The sliding and pressing mechanism  210  is disposed below the front panel  120  to permit sliding movement of the respective input key  111  in vertical or horizontal direction of said mounting hole  121  within the handheld electronic device  100 . 
     The sliding and pressing mechanism  210  includes a plate member disposed below the front panel  120  and formed with a slot unit  211  having a horizontal portion  211 H extending along the length of the mounting hole  121  and a vertical portion  211 V integrally and downwardly extending from the horizontal portion  211 H. The respective input key  111  has a vertical touch rod  113  and two horizontal touch rods  115  projecting transversely from the vertical touch rod  113 . The respective input key  111  further has two sliding arms  112  projecting transversely from the vertical touch rod  113  and disposed at an elevation higher than the horizontal touch rods  115  respectively. The sliding arms  112  extend slidably within the slot unit  211  in the plate member. The vertical touch rod  113  is capable of contacting a first circuit (not shown) of the handheld electronic device  100  so as to generate a first signal when the respective input key  111  is pressed downward relative to the front panel  120  in the vertical direction. Each of the horizontal touch rods  115  is capable of contacting a second circuit (not shown) of the handheld electronic device so as to generate a second when the respective input key  111  is moved along the horizontal direction. 
     The spring unit provides a restoration force that permits the respective input key  111  to retrieve its initial position upon removal of the applied force for moving the respective input key  111  along the vertical or horizontal direction. The spring unit includes a plurality of compression springs  221   a ,  221   b  respectively sleeved around the vertical and horizontal touch rods  115 ,  113  for restoring the respective input key  111  to its initial position upon removal of the applied force. 
       FIG. 3  is a partly sectional view of the second preferred embodiment of the keyboard of the present invention taken along the line A-B in  FIG. 1 . The second preferred embodiment has the structure similar to the first preferred embodiment. 
     The only difference resides in that the spring unit of the second preferred embodiment includes a flexible spring plate  330  that is disposed below the front panel  120  and that has an upper convex portion  331 H adjacent to the front panel  120  and a lower concave portion  331  distal to the front panel  120 . The spring plate  330  is preferably made from flexible materials, such a thin metal strip or plastic material so long it can restore the respective input key  311  to its initial position and so long it can activate the second circuit. The input key  311  has two opposite horizontal touch faces  321   a.    
     The sliding movement of the respective input key  311  along the horizontal direction results in collision of the respective touch face  321   a  of the input key  311  against the upper convex portion  331 H, thereby causing deformation of the spring plate  330  so as to lower the lower concave portion  331  to contact the second circuit (not shown) of the handheld electronic device to generate a second signal. 
     In short, the keyboard of the present invention is compact in size and free from the drawbacks of the prior art keyboard. 
     In above embodiment, although all the three different sets of letters are English letters, they also can be phonetic alphabets and Arabic numerals or symbols without restriction. Besides, the arrangement of the keyboard is not limited to the disclosed embodiment either. 
     While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.