Abstract:
A riser, ridge based touch keypad for a portable electronic device (e.g., mobile phone or flex pointer) is disclosed such that either in a dark environment a person with good eyesight or a person with decreased visual acuity may feel the riser(s) and the ridges representing a unique pattern with the finger in order to find the desired hidden key associated with the unique pattern prior to pressing. A couple of embodiments are also disclosed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The invention relates to touch equipment, and more particularly to a riser, ridge based touch keypad for a portable electronic device (e.g., mobile phone or flex pointer) with improved characteristics. 
         [0003]    2. Description of Related Art 
         [0004]    Conventionally, a mobile phone or flex pointer is equipped with a plurality of keys arranged in rows and columns on its top surface. These keys are either function keys or keys of an alphanumeric keypad. As the trend of minimizing the occupying space of a portable electronic device (e.g., mobile phone or flex pointer), so the area of the keys becomes smaller. Hence, senior citizens or those with decreased visual acuity may find it difficult of using such devices due to poor eyesight. Further, people may find it difficult of using such devices in a dark environment. Thus, a need for improvement exists. 
       SUMMARY OF THE INVENTION 
       [0005]    It is therefore one object of the invention to provide a riser, ridge based touch keypad for a portable electronic device (e.g., mobile phone or flex pointer) such that either in a dark environment a person with good eyesight or a person with decreased visual acuity may feel the riser(s) and the ridges representing a unique pattern with the finger in order to find the desired key associated with the unique pattern prior to pressing. 
         [0006]    In one aspect of the invention there is provided a touch keypad mountable on a portable electronic device comprising a flexible touch panel including a longitudinal rail raised along either side of a top surface the electronic device, either rail including a plurality of projections of different lengths extending transversely toward a longitudinal center line of the electronic device, each projection having one or more raised parallel ridges arranged as a unique pattern, a plurality of hidden keys formed under the top surface of the electronic device, and a plurality of pegs each integrally formed with the hidden key and projecting downward; and a film circuit board mounted under the touch panel and including a plurality of top terminals each disposed under the peg by a predetermined distance, whereby in a typing operation feeling the patterns with the finger by the guidance of the rails and the ridges to find the desired projection, and pressing the hidden key immediately adjacent the desired projection will cause the peg under the pressed hidden key to contact the terminal to send an electrical signal representing the pressed hidden key to a processor of the electronic device for processing. 
         [0007]    In another aspect of the invention there is provided a touch keypad mountable on a portable electronic device comprising a flexible touch panel including a longitudinal rail raised along a center line of a top surface the electronic device, the rail including a plurality of projections of different lengths extending transversely from either side, each projection having one or more raised parallel ridges arranged as a unique pattern, and a plurality of hidden keys formed under the top surface of the electronic device; and capacitive sensing means mounted under the touch panel and including two conductive layers each having a plurality of sensor zones, and an insulative layer sandwiched between the conductive layers, wherein each sensor zone of the upper conductive layer is aligned with the hidden key and is spaced apart by a predetermined distance, and the sensor zones of the upper conductive layer are aligned with the sensor zones of the lower conductive layer, whereby in a typing operation feeling the patterns with the finger by the guidance of the rails and the ridges to find the desired projection, and pressing the hidden key immediately adjacent the desired projection will change a capacitance between the pressed hidden key and the sensor zone of the upper conductive layer and send an electrical signal representing the pressed hidden key to a processor of the electronic device for processing. 
         [0008]    The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a mobile phone incorporating a first preferred embodiment of touch keypad according to the invention; 
           [0010]      FIG. 2  is an exploded view of touch panel and film circuit board of the touch keypad shown in  FIG. 1 ; 
           [0011]      FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 1  showing alignment of hidden key and terminal for effecting a correct finger pressing; 
           [0012]      FIG. 4  is a perspective view of a flex pointer incorporating a second preferred embodiment of touch keypad according to the invention; and 
           [0013]      FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 4  showing alignment of key and sensor zone for effecting a correct finger pressing. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    Referring to  FIGS. 1 to 3 , a mobile phone incorporating a first preferred embodiment of touch keypad  10  according to the invention is shown. The touch keypad  10  comprises a thin touch panel  11  and an underlying film circuit board  18 . Each component is discussed in detailed below. 
         [0015]    The touch panel  11  is formed of thermoplastic material and comprises a longitudinal rail  12  along either side of the mobile phone. The rail  12  has a length of about half of the height of the mobile phone in an upright position. The rail  12  raises a predetermined distance from a top surface of the mobile phone. The rail  12  comprises a plurality of (five are shown) short projections  13  extending transversely toward the other rail  12 . The projections  13  extending from the same rail  12  are of different lengths. The projection  13  has one or more raised parallel ridges  131  arranged as a pattern which is adapted to feel by the finger. The rail  12  may shape as a curve or an oblique line other than the shown straight line in other embodiments. 
         [0016]    A plurality of circular flat hidden keys  14  are formed under the top surface of the mobile phone and are defined between a display (not numbered) and the rails  12 . A plurality of projecting pegs  16  each is integrally formed with the hidden key  14  and projects downward. A plurality of (four representing top, down, left, and right) raised function keys  15  of triangle are formed between the display and the rails  12 . Each function key  15  is associated with a specific hidden key  14  disposed adjacent therewith. 
         [0017]    The film circuit board  18  is comprised of a plurality of thin layers laminated together. The film circuit board  18  comprises a plurality of terminals  19  on a top surface. Each terminal  19  is disposed under the corresponding peg  16  by a short predetermined distance. 
         [0018]    An operation of the invention will be described in detailed below. Either in a dark environment a visually good person or a person with decreased visual acuity may feel the patterns (i.e., the ridges  131 ) with the finger. For example, the front left projection  13  representing numeral “0” is the key to be pressed. Thus, the person may press the hidden key  14  immediately adjacent the front left projection  13  by the guidance of the left rail  12  and the ridges  131  (see  FIG. 1 ). And in turn, the peg  16  under the pressed hidden key  14  contacts the corresponding terminal  19 . As such, an electrical circuit is temporarily formed and an electrical signal representing the numeral “0” is sent to a microprocessor of the mobile phone for processing. This completes a single operation of typing. 
         [0019]    Referring to  FIGS. 4 and 5 , a mobile phone incorporating a second preferred embodiment of touch keypad  20  according to the invention is shown. The touch keypad  20  comprises a thin touch panel  21  and an underlying capacitive sensing member  28 . Each component is discussed in detailed below. 
         [0020]    The touch panel  21  is formed of thermoplastic material and comprises a longitudinal rail  22  along a center line of the flex pointer. The rail  22  has a length of more than half of the height of the flex pointer in an upright position. The rail  22  raises a predetermined distance from a top surface of the flex pointer. The rail  22  comprises a plurality of (five are shown) short projections  23  extending transversely from either side. The projections  23  extending from the same side of the rail  22  are of different lengths. The projection  23  has one or more raised parallel ridges  231  arranged as a pattern which is adapted to feel by the finger. The rail  22  may shape as a curve or an oblique line other than the shown straight line in other embodiments. 
         [0021]    A plurality of circular flat hidden keys  24  are formed under the top surface of the flex pointer and each is located immediately adjacent an open end of the projection  23 . A plurality of (four representing top, down, left, and right) raised function keys  25  of triangle are formed between a front end of the flex pointer and the rail  22 . Each function key  25  is associated with a specific hidden key  24  disposed adjacent therewith. 
         [0022]    The capacitive sensing member  28  is capacitive and is comprised of two conductive layers  281  and an insulative layer  283  sandwiched therebetween. A plurality of sensor zones  282  are formed in each conductive layer  281 . Each sensor zone  282  is aligned with an underside of the hidden key  24  and is spaced apart by a short predetermined distance. Also, the sensor zones  282  of the upper conductive layer  281  are aligned with the sensor zones  282  of the lower conductive layer  281 . 
         [0023]    An operation of the invention will be described in detailed below. Either in a dark environment a visually good person or a person with decreased visual acuity may feel the patterns (i.e., the ridges  231 ) with the finger. For example, the front left projection  23  representing numeral “0” is the key to be pressed. Thus, the person may press the hidden key  24  immediately adjacent the front left projection  23  by the guidance of the rail  22  and the ridges  231  (see  FIG. 4 ). And in turn, a capacitance between the pressed hidden key  24  and the sensor zone  282  of the upper conductive layer  281  thereunder changes due to a distance change therebetween. As such, an electrical circuit is temporarily formed and an electrical signal representing the numeral “0” is sent to a microprocessor of the mobile phone for processing. This completes a single operation of typing. 
         [0024]    The invention has additional advantages as below. Its resolution is high, i.e., high sensitivity in typing operation. Further, it is small and lightweight and can meet the trend of miniaturization. 
         [0025]    While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.