Abstract:
A touch pad character entering system and method are disclosed. The system comprises a touch pad configured to detect contacts by an object thereon, a coordinate extraction module configured to extract coordinates of the contact locations detected by the touch pad, and a processing unit configured to obtain an initial contact coordinate and a subsequent movement by the object in contact with the touch pad from the extracted contact coordinates, select a predetermined group of characters based on the initial contact coordinate, and select a predetermined character from the predetermined group of characters based on the subsequent movement.

Description:
BACKGROUND 
       [0001]    The present invention relates generally to keyboards for entering characters into electronic devices, and, more particularly, to a touch-type keyboard with reduced number of keys. 
         [0002]    Keyboard is the most common device for entering text or instructions into a computational electronic device such as a computer. In general, a keyboard has a plurality of keys, and a single character is assigned to each of the keys. In some cases, a single key can be used to enter two different characters by combining with another key. For instance, when a “Shift” key and a regular letter key are pressed at the same, a capital letter that key represents is entered.  FIG. 1  illustrates a conventional touch pad keyboard  100  for entering letters into a handheld device. The surface area of the touch pad  100  is divided into a plurality of marked regions. Each region represents a letter. For instance, a region  110  represents English letter Z. Once a finger touches the region  110 , letter Z is entered into the handheld device. 
         [0003]    Since English language, as well as many other languages, has twenty six letters, the conventional touch pad keyboard  100  would need to be divided into at least 26 regions. Then each region has to be relatively small, and can be difficult for adult finger to touch precisely. 
         [0004]    As such, what is desired is a system and method to reduce the number of keys required to enter characters in a small form-factor electronic device. 
       SUMMARY 
       [0005]    The present invention discloses a touch pad character entering system and method. The system comprises a touch pad configured to detect contacts by an object thereon, a coordinate extraction module configured to extract coordinates of the contact locations detected by the touch pad, and a processing unit configured to obtain an initial contact coordinate and a subsequent movement by the object in contact with the touch pad from the extracted contact coordinates, select a predetermined group of characters based on the initial contact coordinate, and select a predetermined character from the predetermined group of characters based on the subsequent movement. 
         [0006]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]      FIG. 1  illustrates a conventional touch pad keyboard for entering letters into a handheld device. 
           [0008]      FIG. 2  illustrates a touch pad keyboard with each key region being able to enter multiple characters according to an embodiment of the present invention. 
           [0009]      FIG. 3  illustrates finger motions on one of the key regions of  FIG. 2 . 
           [0010]      FIG. 4  is a block diagram of a character entering system implementing the touch pad keyboard of  FIG. 2 . 
           [0011]      FIG. 5  is a flow chart illustrating operation steps for implementing the touch pad keyboard of  FIG. 2 . 
       
    
    
       [0012]    The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings, wherein like reference numbers (if they occur in more than one view) designate the same elements. The invention may be better understood by reference to one or more of these drawings in combination with the description presented herein. 
       DESCRIPTION 
       [0013]    The following will provide a detailed description of a touch pad keyboard for entering large number of characters with reduced number of keys. 
         [0014]      FIG. 2  illustrates a touch pad keyboard  200  with each key region capable for entering multiple characters according to an embodiment of the present invention. For instance, one of the key regions  210  can be used to enter four letters: Z, X, C, V. As a result, twenty six letters will require only seven key regions, which is a significant reduction in the number of key regions. Therefore, each key region  210  can be larger than the conventional key region  110  of  FIG. 1 , or a size of the touch pad keyboard  200  can be smaller than the conventional touch pad keyboard  100  of  FIG. 1 . 
         [0015]      FIG. 3  illustrates finger motions on one of the key regions  210  of  FIG. 2 . Referring to  FIG. 3A , a spot  310  represents an initial touch area by a finger (not shown) on the key region  210 . The spot  310  is at approximately a center of the key region  210 . A path  312  represents a slide path following the initial touch by the finger on the touch pad  200 , i.e., the finger was sliding upward. Combining the facts that the finger initially touches the key region  210  and then slides upward on the touch pad  200 , this particular finger operation is interpreted as entering letter X according to the embodiment of the present invention. 
         [0016]    Referring back to  FIG. 3A , the path  312  goes to outside of the key region  210  and may enter into a neighboring key region (not shown). As long as the finger maintains contact with the touch key board  200  throughout the slide path  312 , any subsequent finger location is not considered initial contact location. For entering another character, a user has to lift his or her finger off the touch key board  200  and then makes another initial contact with the touch key board  200 . 
         [0017]    Referring to  FIG. 3B , spot  320  represents another initial touch area by a finger (not shown) on the key region  210 . Even though the spot  320  is not centered, it is still within the key region  210 . A path  322  represents a slide path following the initial touch by the finger on the touch pad  200 , i.e., the finger was sliding toward a right. Combining the facts that the finger initially touches the key region  210  and then slides toward the right, this particular finger operation is interpreted as entering letter V according to the embodiment of the present invention. 
         [0018]    Referring to both  FIGS. 3A and 3B , although the key region  210  is shown to be able to enter four different letters, one having ordinary skill in the art would recognize that more than four letters can be entered by the single key region  210  as long as the same number of finger slide directions can be effectively distinguished. For instance, when diagonal slide directions, as well as the orthogonal slide directions, are employed, a single key region can represent a total of eight letters. 
         [0019]      FIG. 4  is a block diagram of a character entering system  400  implementing the touch pad keyboard  200  of  FIG. 2 . The character entering system  400  include a touch pad  402 , a coordinate extraction module  412 , a processing unit  422  and an optional display  432 . The touch pad  402  is a well known pointing device comprising a specialized surface that can continuously sense locations of a user&#39;s finger on the touch pad  402 . Signals generated by the touch pad  402  corresponding to the finger touch locations are then sent to the coordinate extraction module  412  which translate the signals into coordinate values. The processing unit  422  detects a coordinate of a finger&#39;s initial contact location, and then detects a finger slide direction immediately following the initial contact. The processing unit  422  then combines the initial contact coordinate with the finger slide direction to determine which letter the finger intends to enter. According to the embodiment of the present invention, the initial contact coordinate selects a predetermined group of letters. The slide direction selects a particular letter from the predetermined group of letters. For instance, referring back to  FIG. 3A , the spot  310  is translated into an initial contact coordinate. Since the spot  310  is within the key region  210 , then the spot  310  selects the group of letters: Z, X, C, V. The slide path  312  is translated as an upward slide direction, then letter X is determined to be the letter the finger is intended to enter. In a touch pad in which a display screen overlays key regions, the optional display unit  432  may display the selected letter X in proximity of the initially contacted key region to confirm the righteousness of the key stroke. 
         [0020]    In detecting the initial contact coordinate and the slide direction, fuzzy logic and/or other optimization program may be applied to determine best values for these parameters. In case that a key stroke includes only an initial contact by a finger without any slide motion following the initial contact and before the finger being lifted away from the touch pad keyboard  200 , the character entering system  400  may not be able to determine a selected letter for the key stroke. An alternative is to assign a default letter to a key region, when there is no finger slide being detected after an initial contact and before the finger is lifted, the default letter is then determined to be entered. Another option is to assign a different letter to a contact-only-and-no-slide key stroke. For instance, referring back to  FIG. 3A , a numerical character “0” may be assigned to the key region  210  for a contact-only-and-no-slide key stroke in addition to the aforementioned four letters. 
         [0021]      FIG. 5  is a flow chart illustrating operation steps for implementing the touch pad keyboard of  FIG. 2 . In step  502 , an initial finger contact with the touch pad is detected and coordinates of the initial contact spot is extracted. In step  512 , finger movement information, including a slide direction on the touch pad immediately subsequent to the initial contact is detected. Here the movement that immediately subsequent to the initial contact is chosen to be detected because that period of finger movement is most representative of a user&#39;s intension in terms of character entering. A user may slide his or her finger sequentially in different directions after an initial contact, but only the first direction that counts according to the embodiment of the present invention. Apparently, this is only a design choice, or a best mode of operation. 
         [0022]    In step  522 , the initial contact coordinates and the subsequent finger movement information are combined to derive a third parameter. In step  532 , a character value is determined, i.e., a character is selected, based on the third parameter. 
         [0023]    The above illustration provides many different embodiments or embodiments for implementing different features of the invention. Specific embodiments of components and processes are described to help clarify the invention. These are, of course, merely embodiments and are not intended to limit the invention from that described in the claims. 
         [0024]    Although the invention is illustrated and described herein as embodied in one or more specific examples, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention, as set forth in the following claims.