Patent Publication Number: US-2005134576-A1

Title: Handheld electronic device with touch control input module

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority of Chinese Appln. No. 200310121523.3, filed on Dec. 19, 2003.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a handheld electronic device, more particularly to a handheld electronic device with a touch control input module.  
      2. Description of the Related Art  
      Most portable electronic products rely on a keyboard consisting of a plurality of keys as a primary data input medium. Although the manufacturing technologies of both keys and keyboards are quite mature, and the component costs thereof have considerably dropped over the years, the number of components needed for assembly is still rather large. As such, the entire structure remains relatively complicated, thus incurring high assembly costs. Accordingly, the effect of lowering production costs through simplification of production flow is limited. Besides, in the past, the low cost of individual components is achieved by mass production through mold techniques. However, current trends toward customization and personalization of electronic products require the fabrication of various components in different styles at relatively small quantities. Hence, manufacturing costs are not lowered when customized keys and keyboard devices are fabricated using mold techniques commonly used in mass production. Moreover, current electronic products, such as mobile phones, notebook computers, etc., are designed to meet consumer demands, such as lighter, thinner, shorter, smaller, etc. Due to the present trend toward miniaturization, providing electronic products with keys and keyboards as input modules will unavoidably incur higher manufacturing costs in view of the pursuit for accuracy and the difficulty in assembling miniaturized components. Accordingly, miniaturized electronic products with keys and keyboards tend to lose their competitive edge in the market.  
      On the other hand, since a touch control input module provides advantages, such as user-friendliness and small operating space requirement, a growing number of electronic products incorporate the touch control input module as an optional man-machine interface. Particularly, not only do current notebook computers include touch control pads, some mobile phones also incorporate touch control panels, which provide a handwriting function on their screens. Furthermore, handheld electronic devices, such as personal digital assistants (PDA), tablet personal computers, etc., include touch control screens that serve as primary data input/output modules.  
      However, the touch control pads on some electronic products, such as notebook computers, are designed primarily for a handwriting function, which involves generation of relative coordinates similar to those associated with a computer mouse. Particularly, input commands, such as those for controlling cursor movement, are interpreted according to distance and direction of consecutive user contact with the touch control pad. On the other hand, as the touch control screens of other electronic products, such as PDAs and tablet personal computers, serve as primary data input/output modules, many restrictions are encountered in view of the need to provide for both data input and output functions at the same time. For instance, the material for fabricating the touch control screen is limited to light-transmissible conductive glass, which not only mandates higher costs, but also suffers from inferior characteristics, such as durability, flexibility, etc. Furthermore, since data display through the touch control screen proceeds by way of image projection, there is a need to switch the operating mode of the touch control screen before the latter can act as a data input module. As such, data input through the touch control screen is both inconvenient and time-consuming. In addition, when the touch control screen is frequently used for data input, the battery power of the electronic product is quickly exhausted, and the service life of the touch control screen is shortened as well.  
      Moreover, since conductive glass is needed for fabrication, due to limitations of current manufacturing technology, the touch control screen can only be designed in the form of a rectangular flat plate, which precludes fabrication in other shapes, such as curved, circular, polygonal other than rectangular, etc. Therefore, the touch control screen is unsuitable for uniquely designed casings of electronic products, and is hence seldom applied to customized and miniaturized modern electronic products.  
      Furthermore, when the electronic device is primarily for input use, such as a remote controller, or is primarily for outputting non-visual information, such as portable radios, use of the aforesaid touch control screen having both input and output functions not only increases costs, but also introduces adverse affects to user convenience and durability of the electronic device.  
     SUMMARY OF THE INVENTION  
      Therefore, the object of the present invention is to provide an electronic device with a touch control input module that can overcome the aforesaid drawbacks associated with the prior art.  
      According to one aspect of the present invention, there is provided a handheld electronic device that comprises a case body, a touch control input module, and a processing device. The touch control input module is mounted on the case body, and includes a protective layer, a sensing layer, and a signal processing unit. The protective layer has an outer surface exposed from the case body, and an inner surface opposite to the outer surface. The outer surface is defined with a plurality of contact regions, each of which is marked with a symbol. The sensing layer is in contact with the inner surface of the protective layer, and is responsive to contact of an object with the outer surface of the protective layer so as to generate an electrical output indicative of contact position of the object with the outer surface of the protective layer. The signal processing unit is coupled electrically to the sensing layer for receiving the electrical output and for generating a control output corresponding to the electrical output. The processing device is disposed in the case body, is coupled electrically to the signal processing unit, and is responsive to the control output from the signal processing unit so as to perform an operation associated with the control output.  
      According to another aspect of the present invention, there is provided a touch control input module that includes a protective layer, a sensing layer, and a signal processing unit. The protective layer has opposite outer and inner surfaces. The outer surface is defined with a plurality of contact regions, each of which is marked with a symbol. The sensing layer is in contact with the inner surface of the protective layer, and is responsive to contact of an object with the outer surface of the protective layer so as to generate an electrical output indicative of contact position of the object with the outer surface of the protective layer. The signal processing unit is coupled electrically to the sensing layer for receiving the electrical output and for generating a control output corresponding to the electrical output. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:  
       FIG. 1  is a schematic view of the first preferred embodiment of a handheld electronic device according to the present invention;  
       FIG. 2  illustrates a touch control input module of the first preferred embodiment; and  
       FIG. 3  is a schematic view of the second preferred embodiment of a handheld electronic device according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      As shown in  FIGS. 1 and 2 , the first preferred embodiment of a handheld electronic device  2  according to the present invention is shown to be embodied in a mobile phone, and includes a case body  3  with a curved surface  31 , a touch control input module  1  mounted on the case body  3 , a display module  4  mounted on the case body  3 , and a processing device  6  coupled electrically to the touch control input module land the display module  4 , and disposed in the case body  3 . The case body  3  is further formed with a recessed area  30  in the curved surface  31 .  
      The touch control input module  1  includes a protective layer  11 , a sensing layer  12 , and a signal processing unit  10 .  
      The protective layer  11  is disposed in the recessed area  30  in the curved surface  31  of the case body  3 , and has an outer surface  111  exposed from the curved surface  31  of the case body  3 , and an inner surface  112  opposite to the outer surface  111 . The outer surface  111  is defined with a plurality of contact regions  5 , each of which is marked with a symbol  51 . In this embodiment, the protective layer  11  is made of a flexible plastic material, and the outer surface  111  is a curved surface so as to complement the curved surface  31  of the case body  3 . However, it should be noted herein that the outer surface  111  need not necessarily be a curved surface, and can be in the form of a flat surface to suit a flat surface of a case body.  
      In this embodiment, the contact regions  5  provide the electronic device  2  with the functions of a telephone keypad, and are grouped into a numerical block  55 , a directional block  56  and a functional block  57 . The contact regions  5  in the numerical block  55  are marked with mutually distinct numerical symbols  515 . The contact regions  5  in the directional block  56  are marked with mutually distinct arrow symbols  516 . Some of the contact regions  5  in the functional block  57  are marked with distinct handset symbols  517  (i.e., a handset on-hook symbol and a handset off-hook symbol). In this embodiment, the contact regions  5  and the symbols  51  are printed on the outer surface  111  through an intaglio printing technique using a paint material that contains a phosphorescent material. However, printing of the same on the outer surface  111  may be conducted through other printing techniques, such as lithographic and relief printing. Moreover, the paint material maybe mixed with a fluorescent material, or may be one whose color characteristics vary according to the ambient light or the ambient temperature condition for enhancing visual appeal.  
      In this embodiment, the contact regions  5  and the symbols  51 , which are printed on the outer surface  111  through an intaglio printing technique, project from the outer surface  111  of the protective layer  11 . However, depending on the material of the protective layer  11 , other methods, such as thermal press-forming and laser cutting, are available for forming the contact regions  5  and the symbols  51  that project from the outer surface  111 . In other embodiments, the same methods are applicable to engrave the contact regions  5  and the symbols  51  in the outer surface  111  of the protective layer  11 .  
      The sensing layer  12  is in contact with the inner surface  112  of the protective layer  11 , and is responsive to contact of an object (not shown) with the outer surface  111  of the protective layer  11  so as to generate an analog electrical output indicative of contact position of the object with the outer surface  111  of the protective layer  11  in a conventional manner. In this embodiment, the sensing layer  12  is a capacitive-type sensing layer, and senses a contact position of the object with the outer surface  111  of the protective layer  11  through a feed current that is generated as a result of variation in capacitance when static electricity of the object couples with an electrode array. It should be noted herein that other types of sensing layers  12 , such as resistive or electromagnetic, are also applicable to the present invention. Since the main technical feature of this invention does not reside in the specific configuration and operation of the sensing layer  12 , which are well known to those skilled in the art, further details are omitted herein for the sake of brevity.  
      The signal processing unit  10  is coupled electrically to the sensing layer  12  for receiving the electrical output and for generating a control output corresponding to the electrical output. In this embodiment, the signal processing unit  10  includes a coordinate computing unit  13 , an encoder  14 , and a mode control unit  15 .  
      The coordinate computing unit  13  is coupled electrically to the sensing layer  11  for receiving the electrical output and for generating a coordinate output corresponding to the electrical output. The encoder  14  is coupled electrically to the coordinate computing unit  13  for receiving the coordinate output and for generating the control output that corresponds to the coordinate output. In this embodiment, the encoder  14  is operable in a selected one of a default key input mode, where the control output generated by the encoder  14  corresponds to the symbol  51  marked on the contact region  5  that is associated with the coordinate output from the coordinate computing unit  13 , and a handwriting input mode, where the control output generated by the encoder  14  corresponds to movement of the object on the outer surface  111  of the protective layer  11 . The mode control unit  15  is coupled electrically to the processing device  6  and the encoder  14 , and is associated operably with the encoder  14  for enabling operation of the encoder  14  in the selected one of the key input mode and the handwriting input mode. In practice, the aforesaid coordinate computing unit  13 , the encoder  14  and the mode control unit  15  can be incorporated into a single integrated circuit chip (not shown).  
      When it is intended to perform an operation, such as inputting a set of numerical digits, the user simply uses his finger to press the contact regions  5  marked with the selected numerical symbols  515  in the numerical block  55 . Subsequently, the sensing layer  12  senses contact positions of the user&#39;s finger with the outer surface  111  of the protective layer  11 , and generates analog electrical outputs corresponding to the sensed contact positions for reception by the coordinate computing unit  13 . The coordinate computing unit  13  then calculates coordinate outputs based on the electrical outputs, and provides the coordinate outputs to the encoder  14 . In response to the coordinate outputs, the encoder  14  generates control outputs that correspond to the selected numerical symbols  515 . The processing device  6  receives and processes the control outputs, and subsequently performs an operation associated with the control outputs, such as controlling the display module  4  to display the selected numerical symbols  515  thereon.  
      When operation in the handwriting mode is intended, the user first presses a designated contact region  5  in the functional block  57  that is designated for the mode control function. The sensing layer  12  senses the contact position of the user&#39;s finger with the outer surface  111  of the protective layer  11 , and generates the analog electrical output corresponding to the sensed contact position for reception by the coordinate computing unit  13 . The coordinate computing unit  13  then calculates the coordinate output based on the electrical output, and provides the coordinate output to the encoder  14 . In response to the coordinate output, the encoder  14  generates the control output that corresponds to the designated contact region  5 . The processing device  6  receives and processes the control output, and subsequently issues a mode switch command to the mode control unit  15  so as to enable operation of the encoder  14  in the handwriting input mode. Thereafter, when the user writes over the contact regions  5  in the numerical block  55 , the sensing layer  12  senses the contact positions of the user&#39;s finger with the outer surface  111  of the protective layer  11 , and generates analog electrical outputs corresponding to the sensed contact positions for reception by the coordinate computing unit  13 . The coordinate computing unit  13  then calculates the coordinate outputs based on the electrical outputs, and provides the coordinate outputs to the encoder  14 . In response to the coordinate outputs, the encoder  14  generates continuous control outputs corresponding to movement of the user&#39;s finger on the outer surface  111  of the protective layer  11  for processing by the processing device  6 . Finally, the aforesaid mode switching operation is repeated when it is intended to switch operation back to the key input mode.  
      Instead of designating a contact region  5  in the functional block  57  for mode switching control, the mode control unit  15  can be configured to switch operation of the encoder  14  between the key input and handwriting input modes automatically by detecting whether the coordinate outputs from the coordinate computing unit  13  indicate crossing of a predefined set of adjacent contact regions  5 .  
      Furthermore, the outer surface  111  of the protective layer  11  may be configured with at least a designated block that contains at least an adjacent pair of the contact regions  5 . In practice, the number of the designated blocks can vary according to actual design requirements. In this embodiment, the designated block is defined by an adjacent pair of the contact regions  5  in the functional block  57 , is assigned to a scroll-up or scroll-down function, and is thus named as a scrolling block  501 . The control output generated by the encoder  14  corresponds to the scrolling block  501  when successive ones of the coordinate outputs from the coordinate computing unit  13  within a predetermined time period indicate movement of an object from one of the contact regions  5  in the adjacent pair to the other of the contact regions  5  in the adjacent pair. The control output that corresponds to the scrolling block  501  is then interpreted by the processing device  6  as a scroll-up or scroll-down command.  
      In this embodiment, the predetermined time period is 1 second. Therefore, when the user uses his finger to touch the scrolling block  501 , and slides his finger within the 1-second predetermined time period from one of the contact regions  5  in the scrolling block  501  to the other of the contact regions  5  in the scrolling block  501  in a direction away from the display module  4 , the consecutive coordinate outputs generated through the sensing of the sensing layer  12  and the calculation of the coordinate computing unit  13  indicate such movement and are subsequently interpreted by the encoder  14  as a scroll-down control output to be received by the processing device  6  so as to control scrolling of names, numbers or messages shown on the display module  4 . Scroll-up control of the display module  4  proceeds in a similar manner. However, when it is intended to issue a scroll-up control output to the processing device  6 , the user slides his finger within the 1-second predetermined time period from one of the contact regions  5  in the scrolling block  501  to the other of the contact regions  5  in the scrolling block  501  in a direction toward the display module  4 .  
      In a modified embodiment, the handheld electronic device  2  is provided with a multi-media playback function. When playing a movie or an animation, the contact region  5  marked with a right arrow symbol  516  in the directional block  56  is configured for a forward play function, whereas the contact region  5  marked with a left arrow symbol  516  in the directional block  56  is configured for a reverse play function. The outer surface  111  of the protective layer  11  is further configured with a playback block  502  that contains all of the contact regions  5  in the directional block  56 . Therefore, when the user uses his finger to touch the playback block  502 , and rotates his finger about the playback block  502  in a clockwise direction within the 1-second predetermined time period, the coordinate outputs generated through the sensing of the sensing layer  12  and the calculation of the coordinate computing unit  13  indicate such movement and are subsequently interpreted by the encoder  14  as a fast-forward control output to be received by the processing device  6  for activating a fast-forward operation of the latter.  
      In the same token, when the user uses his finger to touch the playback block  502 , and rotates his finger about the playback block  502  in a counterclockwise direction within the 1-second predetermined time period, the coordinate outputs generated through the sensing of the sensing layer  12  and the calculation of the coordinate computing unit  13  indicate such movement and are subsequently interpreted by the encoder  14  as a fast-rewind control output to be received by the processing device  6  for activating a fast-rewind operation of the latter.  
      As shown in  FIG. 3 , the second preferred embodiment of a handheld electronic device  2  according to the present invention is shown to be embodied in a palm computer, which is designed for a special task, such as for use by policemen to verify license plates and personal identification, or for use by express delivery and cargo delivery personnel to facilitate delivery tracking and inventory control. The devices  2  of these types are available indifferent forms, and are required to bear frequent input activity for long periods of time.  
      The handheld electronic device  2  of this embodiment also includes a case body  3 , a touch control input module  1  mounted on the case body  3 , a display module  4  mounted on the case body  3 , and a processing device (not shown) coupled electrically to the touch control input module  1  and the display module  4 , and disposed in the case body  3 . The case body  3  is also formed with a recessed area  30 .  
      In this embodiment, the touch control input module  1  is substantially similar to that of the first preferred embodiment. To meet operating requirements, the contact regions  5  of the touch control input module  1  are likewise grouped into a numerical block  55  and a functional block  57 . The contact regions  5  in the numerical block  55  are marked with mutually distinct numerical symbols  515 . The contact regions  5  in the functional block  57  are marked with mutually distinct function symbols  517 . Unlike the first preferred embodiment, the touch control input module  1  of this embodiment is further defined with a pair of scrolling blocks  501 , each of which contains a distinct contact region  5 . In this embodiment, the scrolling blocks  501  extend in mutually orthogonal directions, and are configured for left/right and up/down scrolling control, respectively. Therefore, when the user uses his finger to touch any one of the scrolling blocks  501 , and drags his finger along the length of the distinct contact region  5  contained in the scrolling block  501  within the 1-second predetermined time period, the coordinate outputs generated through the sensing of the sensing layer  12  and the calculation of the coordinate computing unit  13  indicate such movement and are subsequently interpreted by the encoder  14  as a corresponding scrolling control output to be received by the processing device so as to enable the latter to perform the desired scrolling operation.  
      In sum, the handheld electronic device  2  of this invention uses the modularized touch control input module  1  that is manufactured using thin-membrane technology as a replacement for conventional keys and keyboards. Not only can manufacturing costs be reduced, production process is also simplified in view of automated manufacturing. Furthermore, this invention also fits the current marketing trend toward customization, and the thin-membrane technology also makes the handheld electronic device  2  lighter, thinner, shorter, smaller and more stylish, which are preferred by consumers nowadays.  
      Moreover, since the touch control input module  1  is dedicated for data input use, it is not restricted in terms of material for fabrication and shape of the case body. The possibility of adopting more durable and flexible materials also increases the competitive edge for this invention. In addition, there is no need for switching between data input and output modes as commonly encountered when conventional touch control screens are in use. The advantageous effects of this invention as compared to devices that incorporate conventional touch control screens are more evident when this invention is used outdoors.  
      In addition, when the electronic device is primarily for input use, such as a remote controller, or is primarily for outputting non-visual information, such as portable radios, use of the aforesaid touch control input module  1  not only results in lower costs, but also provides advantages in terms of user convenience and durability.  
      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.