Abstract:
Embodiments of the present invention include a stylus for use with a touch screen having a digitizer, the stylus being configured to fit comfortably in the hand of the user and comprises: an elastic segment; an operating end tapered to a point coupled to the elastic segment; a second end cap coupled to the elastic segment and a plurality of mid-segments coupled to the elastic segment. In one embodiment the stylus comprises four different parts including a tip, an end cap, mid-segments and an elastic member. Furthermore, in one embodiment, a simple spring is used to attach the tip, the end cap and the mid-segments. The stylus can be locked into place while in use or can be bent to conform to the geometry of the portable electronic device. The result is a bi-stable stylus sized to conform to a user&#39;s hand that can be stored on smaller dimensioned portable electronic devices. Additionally, the cost of manufacturing such a stylus is reduced because the variety of parts is minimal.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to the field of data input devices. More particularly, embodiments of the present invention relate to the field of stylus input device aids. 
     RELATED ART 
     A Personal Digital Assistant (commonly referred to as a PDA) is a portable computer system. The PDA is a portable handheld device that is used as an electronic organizer which has the capability to store a wide range of information that includes daily appointments, numerous telephone numbers of business and personal acquaintances, and various other information. Furthermore, the Personal Digital Assistant has the ability to connect to a personal computer system, enabling the two devices to exchange updated information. Additionally, the PDA can be connected to a modem, enabling it to have electronic mail (e-mail) capabilities over the Internet along with other Internet capabilities over a wireless communication interface. Also, the Personal Digital Assistant can be coupled to a networking environment. 
     Typically, the PDA includes a data input device such as a handwriting recognition device that can be utilized to control and operate the PDA. The handwriting recognition device receives user input as handwriting stroke data, where a user utilizes a stylus to stroke alphanumeric characters and analog characters (e.g., *, &amp;, @, $, etc.) on the handwriting recognition device. The handwriting recognition device processes the handwriting stroke data and transmits the processed data to another component (e.g., an electronic display device, a memory unit, a processor, etc.) of the PDA so that a particular operation or function can be performed. PDAs are enormously popular, in part because of their handwriting recognition device. 
     However, as PDA technology becomes more sophisticated, the size of the PDA becomes smaller and smaller. As a result, the size of the input device or stylus has also been miniaturized to conform to the smaller size of the PDA. While most users prefer the smaller, less bulky design of the PDA, many find that the smaller size of the stylus is difficult to use, inhibits performance and may cause problems such as hand cramping and wrist strain. Many users use the stylus input device in a similar manor that they use a pen or pencil. Therefore, a miniature stylus can cause users to feel unfamiliar with the device and thus create user frustration. 
     To overcome the problems associated with a miniature stylus, a telescoping stylus has been developed. Prior Art  FIG. 1  illustrates an example of a telescoping stylus  20 . A telescoping stylus can be lengthened when used to give the stylus a much more satisfactory weight and feel. When not in use, the stylus can be collapsed for storage in a PDA&#39;s usual storage slot. One problem associated with the telescoping stylus  20  is the cost to manufacture. To manufacture a telescoping stylus, many different pieces such as different body segments  21  and the tip  22  must be made and then assembled to manufacture the product. As a result, the cost for a telescoping stylus can be considerably more than a standard stylus. Furthermore, when using the telescopic stylus  20 , sometimes the tip collapses in on the body thereby impeding the data entry. 
     Thus, there exists a need for a stylus that conforms to the smaller size of a modern PDA yet provides the user with a comfortable feel as to eliminate hand cramping and wrist strain. In addition, the stylus should be cost effective to produce. 
     SUMMARY OF THE PRESEST INVENTION 
     In accordance with embodiments of the present invention, bi-stable stylus is disclosed to facilitate improved user comfort and data entry associated with smaller dimensioned portable electronic devices. Embodiments of the present invention provide a device that may be used for data entry with a portable electronic device such as a Personal Digital Assistant, a pager, a cell phone, etc. In addition, the present invention does not require special instructions or learning curve as do many data entry aids for personal digital assistants. 
     Embodiments of the present invention include a stylus for use with a touch screen having a digitizer. The bi-stable stylus is configured to fit comfortably in the hand of the user and comprises: an elastic segment; an operating end tapered to a point coupled to the elastic segment; a second end cap coupled to the elastic segment and a plurality of mid-segments coupled to the elastic segment. 
     More specifically, in one embodiment the stylus comprises four different parts including a tip, an end cap, mid-segments and an elastic member. Furthermore, in one embodiment, a simple spring is used to attach the tip, the end cap and the mid-segments. The stylus can be locked into place while in use or can be readily bent to conform to the geometry of the portable electronic device. The result is a stylus sized to conform to a user&#39;s hand that can be stored on smaller dimensioned portable electronic devices. Additionally, the cost of manufacturing the novel stylus is low because the variety of parts is minimal. 
     As discussed, the stylus of one embodiment of the present invention consists of four distinct parts consisting of a tip, mid-segments, an end cap and an elastic or spring part. The spring or elastic part spans between the tip and the end cap. The mid-segments take up the space between the tip and the end cap and have the spring or elastic segment running through the center of the mid segments. The elastic segment traps the mid segments between the end cap and the tip. Since the elastic member is under constant tension, a compressive force is distributed to the mid segments locking them in position while in use. The mid segments nest into each other to form a rigid part. 
     When the elastic member is stretched by pulling the stylus apart, the mid-segments un-nest and the unit can be bent into various shapes. By allowing the stylus to be bent, the novel stylus can be wrapped around the corner of a portable electronic device thus allowing a stylus with a length dimension larger than the length dimension of the portable electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a prior art telescoping stylus used with smaller dimensioned portable electronic devices. 
         FIG. 2  illustrates a network environment, including a handheld electronic device coupled to a host computer system and the Internet via a cradle device, in which embodiments of the present invention can be practiced. 
         FIG. 3  illustrates a logical circuit block diagram of a handheld electronic system in which embodiments of the present invention can be practiced. 
         FIG. 4  is a top-side perspective view of an exemplary Personal Digital Assistant computer system. 
         FIG. 5  is an illustration of a smaller dimensioned exemplary Personal Digital Assistant and a normally dimensioned stylus device. 
         FIG. 6  is an illustration of an exemplary Personal Digital Assistant with a flexible bi-stable stylus wrapped around one of the corners in accordance with an embodiment of the present invention. 
         FIG. 7A  is an illustration of a stretched flexible bi-stable stylus device that can conform to a smaller dimensioned Personal Digital Assistant and is comfortable for the user in accordance with an embodiment of the present invention. 
         FIG. 7B  is an illustration of a flexible bi-stable stylus device in a non-stretched position that can conform to a smaller dimensioned Personal Digital Assistant and is comfortable for the user in accordance with an embodiment of the present invention. 
         FIG. 8A  is an illustration of a stretched flexible bi-stable stylus device incorporating a flexible outer sleeve in accordance with an embodiment of the present invention. 
         FIG. 8B  is an illustration of a flexible bi-stable stylus device in a non-stretched position incorporating a flexible outer sleeve in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross section illustration of a bi-stable stylus mid-segment used in one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be obvious to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention. 
     Although the present invention may be implemented with a variety of different electronic systems such as a pager, a mobile phone, a calculator, a Personal Digital Assistant (PDA), etc., one exemplary embodiment includes the stylus with a portable computing system. It should be understood that the descriptions corresponding to  FIGS. 3–5  provide information regarding an exemplary portable computing system. 
       FIG. 2  illustrates a network environment  151 , including a handheld electronic system (e.g., personal digital assistant  100 ) coupled to a host computer system and the Internet via a cradle device  160 , in which embodiments of the present invention can be practiced. 
     Network environment  151  comprises a host computer system  156  which can either be a desktop computer system as shown, or, alternatively, can be a laptop computer system  158 . Optionally, more than one host computer system  156  can be used within network environment  151 . Host computer system  158  and  156  are shown connected to a communication bus  154 , which in one embodiment can be a serial communication bus, but could be of any of a number of well known designs (e.g., a parallel bus, Ethernet Local Area Network (LAN), etc.). In an embodiment, bus  154  can provide communication with the Internet  152  using a number of well-known protocols. 
     Importantly, bus  154  is also coupled to a cradle  160  for receiving and initiating communication with the personal digital assistant  100 . Cradle  160  provides an electrical and mechanical communication interface between bus  154  (and any device coupled to bus  154 ) and the Personal Digital Assistant  100  for two-way communications. The Personal Digital Assistant  100  also contains a wireless inferred communication mechanism  164  for sending information to other devices and for receiving information from other devices. 
       FIG. 3  is a block diagram of exemplary circuitry of a portable computing system  100  in accordance with one embodiment of the present invention. The computer system  100  includes a central processor for processing information and instructions. It is appreciated that central processor unit  101  may be a microprocessor or any other type of processor. The computer system  100  also includes data storage features such as a volatile memory  102  (e.g., random access memory, static RAM, dynamic RAM, etc.) for storing information and instructions for the central processor  101  and a non-volatile memory  103  (e.g., read only memory, programmable ROM, flash memory, EPROM, EEPROM, etc.) for storing static information and instructions for the processor  101 . Computer system  100  may also include an optional data storage device  104  (e.g., thin profile removable memory) for storing information and instructions. It should be understood that data storage device  104  may be removable. Furthermore, device  104  may also be a secure digital (SD) card reader or equivalent removable memory reader. Also included in computer system  100  of  FIG. 3  is an alphanumeric input device  106  which in one implementation is miniature keyboard and may include integrated push buttons. 
     System  100  of  FIG. 3  also includes an optional cursor control or directing device  107  for communicating user input information and command selections to the central processor  101 . In one implementation, device  107  is a touch screen device (also a digitizer) incorporated with screen  105 . Device  107  is capable of registering a position on the screen  105 . 
     Computer system  100  also contains a flat panel display device  105  for displaying information to the computer user. The display device  105  utilized with the computer system  100  may be a liquid crystal device (LCD), cathode ray tube (CRT), field emission device (FED, also called flat panel CRT), plasma or other display technology suitable for creating graphic images and alphanumeric characters recognizable to the user. In one embodiment, the display  105  is a flat panel multi-mode display capable of both monochrome and color display modes. 
     Also included in computer system  100  of  FIG. 3  is a signal communication device  108  that may be a serial port (or USB port) for enabling system  100  to communicate PC  156 . In one embodiment, the communication interface is a serial communication port, but could also alternatively be of any of a number of well known communication standards and protocols, e.g., parallel, SCSI, Ethernet, Firewire (IEEE 1394), USB, etc. including wireless communication. 
     With reference to  FIG. 4 , a perspective illustration of the top face  100   a  of exemplary Personal Digital Assistant computer system  100  is shown. Top face  100   a  contains a display screen  105  surrounded by a bezel or cover. A removable stylus  80  is also shown. Display screen  105  is a touch screen capable of registering contact between the screen and the tip of stylus  80 . Stylus  80  can be fabricated of any material which can make contact with screen  105 . Top face  100   a  also contains one or more dedicated and/or programmable buttons  75  for selecting information and causing computer system  100  to implement functions. 
     Referring still to  FIG. 4 , a handwriting recognition pad or “digitizer” containing regions  106   a  and  106   b  is also shown. Specifically, region  106   a  is for the drawing of alpha characters therein for automatic recognition and region  106   b  is for the drawing of numeric characters therein for automatic recognition. Stylus  80  is used for stroking a character within one of the regions  106   a  and  106   b . The stroke information is then fed to an internal processor for automatic character recognition. Once characters are recognized, they may be displayed on screen  105  for verification and/or modification. 
       FIG. 5  is a perspective illustration  100   c  of the top face of an exemplary reduced size personal digital assistant computer system  100 . In many configurations, Personal Digital Assistant  100   c  is dimensioned similar to the length of stylus  80 , but as a result of advancing technology, the dimensions of Personal Digital Assistants are decreasing to cater to the demands for a smaller, easy to carry devices. As a result, the size of an ergonomically comfortable stylus  80  is longer than the smaller dimensioned Personal Digital Assistant. To overcome this issue, many manufactures have down-sized the length of the stylus to conform to the smaller dimensioned Personal Digital Assistant. The smaller size of the stylus has resulted in comfort and familiarity issues for the user. Users may experience difficulty using the smaller device. 
       FIG. 6  is an illustration of a Personal Digital Assistant with a bi-stable stylus  200  that wraps around the corner of the device in one embodiment of the present invention. In this embodiment, a full size stylus  200  can be used and stored on the device even though the length of the stylus is larger than the length of the Personal Digital Assistant. In this embodiment, the stylus  200  can be bent around the edge of the device so the stylus does not protrude from the top as it would in many other configurations. In this embodiment the stylus has a plurality of segments that interlock to form the rigid body of the stylus. When the stylus is stored on the PDA, the interlocks can be disconnected and the stylus becomes pliable thus allowing the stylus to conform to the geometry of the PDA. When in use, the mid segments are held in place with an elastic member such as a spring to hold them in place to form a rigid body. 
       FIG. 7A  is an illustration of a flexible bi-stable stylus device that can conform to a smaller dimensioned Personal Digital Assistant and is comfortable for the user. This is an exploded view illustrating the different parts of the stylus in a stretched position. In  FIG. 7A , the stylus is represented in a stretched position as it may appear before storage on an electronic device. The top of  FIG. 7  is the end cap  201 . Attached to the end cap  201  is an elastic member  202 . In this embodiment, the elastic member  202  is a spring and in another embodiment, the elastic member can be a rubber band or a length of any elastic material that provides sufficient tension to hold the mid-segments in a locked position. The spring  202  attaches to the end cap  201  with a hook or any suitable connection for attaching the spring  202  to the end cap  201 . The next elements of the stylus are the mid segments  203 . The mid segments are hollow thus allowing the elastic member  202  to be placed in the center of the stylus. The number of mid segments  203  can vary depending on the dimensions of the mid segments and the desired length of the stylus. The desired length of the stylus can be achieved by altering the number of mid segments used in the manufacturing of the stylus. 
     Lastly, the pointed tip  204  completes the stylus device. Similar to the end cap  201 , the elastic member  202  attaches to the tip  204  with a hook or another suitable connection mechanism. The mid segments  203  and the tip  204  share a common nesting mechanism  222 . The nesting mechanism allows the segments to interlock into each other. For example, one end of the mid segment has a smaller diameter than the other end of the mid segment. As a result, the mid segments can interlock to form a rigid member. 
       FIG. 7B  is an illustration of stylus  200  in a locked position. In  FIG. 7B , the nesting mechanism  222  is interlocked with the mid segments  203  and the end caps  201  and  204  to form a rigid member. In this embodiment, the elastic member is a spring  202  that traverses through the hollow mid segments  203  from the top end cap  201  to the tip  204 . 
       FIG. 8A  is an illustration of a flexible bi-stable stylus device incorporating a flexible outer sleeve. Similar to  FIG. 7 , the stylus  300  incorporates many of the same elements. Referring to the top of  FIG. 8 , the end cap  201  is the same as  FIG. 7 . In addition, the mid segments,  203 , tip  204 , and nesting mechanism  222  are also similar to  FIG. 7 . In this embodiment, the elastic member is on the outside of the interlocking segments. In this embodiment, the elastic member is a tube  230  that is the length of the stylus. The outside elastic member  230  can be made in many different colors and textures to conform to the demands of the user. In another embodiment, the elastic tube  230  is clear and the interlocking mid segments are different colors. In this embodiment, the user can personalize the stylus by interchanging the segments of the stylus thus creating a personalized stylus device. The outer sleeve  230  can be made of any elastic material that provides sufficient tension to hold the mid-segments in a locked position. 
     In this embodiment, the outer tube  230  is under tension and thus holds the interlocking mid segments in place by aligning the nesting mechanism  222 . 
       FIG. 8B  is an illustration of a flexible bi-stable stylus device incorporating a flexible outer sleeve in the locked position. In  FIG. 8B , the nesting mechanism  222  is interlocked with the mid segments  203  and the end caps  201  and  204  to form a rigid member. In this embodiment, the elastic member is an elastic tube that covers the outside of the mid segments  203 . In one embodiment, there is a member  210  that helps align the nesting mechanism  222  when locking the stylus. In one embodiment, the member  210  is a rubber member but it could be any suitable material to aid in the alignment of the nesting mechanism  222 . 
       FIG. 9  is a cross section illustration of a mid-segment used in one embodiment of the present invention. In this illustration, the mid segment  203  and the nesting mechanism  222  are visible. In addition, the elastic member  202  is illustrated. In this embodiment, the mid segments are hollow and the elastic member  202  in the middle of the mid segments. In another embodiment, the elastic member is on the outer diameter of the mid segments. In this embodiment, the elastic member can be a tube. 
     The preferred embodiment of the present invention, a bi-stable stylus device, is thus described. While the present invention has been described in particular embodiments, it should be appreciated that the present invention should not be construed as limited by such embodiments, but rather construed according to the following Claims. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.