Abstract:
A method and apparatus for backlighting a handwriting input area for a portable computing device. The portable computing device includes a display area for displaying alphanumeric data and other images. Underneath the display area is a digitizer input area by which users enter handwritten information into the portable computing device. The portable computing device contains handwriting recognition software which converts the handwritten information into alphanumeric data. Both the display area and the digitizer input area are both backlit to facilitate usage in poor lighting conditions.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of portable computing devices. In particular, the present invention pertains to a method and apparatus for the backlighting of a digitized input area for portable computing devices. 
     2. Related Art 
     As the components required to build a computer system have reduced in size, new categories of computer systems have emerged. One of the new categories of computer systems is the “palmtop” computer system. A palmtop computer system is a computer that is small enough to be held in the hand of a user and can be “palm-sized.” Most palmtop computer systems are used to implement various Personal Information Management (PIM) applications such as an address book, a daily organizer and electronic notepads, to name a few. 
     Since palmtop computer systems are very small, full-sized keyboards are generally not efficient input devices. Palmtop computers using keyboards have keyboard devices that are so small that a user cannot touch-type. Furthermore, to use a keyboard device, a user must either place the palmtop computer system down onto a flat surface, so the user can type with both hands, or the user holds the palmtop computer system with two hands and types with thumbs only. 
     Instead of a keyboard device, some palmtop computers utilize a pen and a digitizer pad as an input system. The pen and digitizer pad combination works well for palmtop computers because the arrangement allows a user to hold the palmtop computer system in one hand while writing with the pen onto the digitizer pad with the other hand. A number of palmtop computer systems that rely on the pen and digitizer pad combination as the primary means of input have been introduced to the market. Most of these pen-based palmtop computer systems provide some type of handwriting recognition system whereby the user can write words and letters on the digitizer pad with a stylus. The palmtop computer system then converts the user&#39;s handwriting into a machine readable format such as ASCII code characters. Examples of pen-based palmtop computer systems that provide handwriting recognition include the Palm Pilot, the Apple Newton, and the Tandy Zoomer devices. 
     Although this combination of a display area with a separate digitizer pad input area has proven to be a success in the marketplace, there some drawbacks. One drawback to this configuration is that the prior art designs do not backlight the digitizer pad. In otherwords, the digitizer pad remains in its passive background color. One of the reasons that prior art palmtop computers have failed to backlight the digitizer pad is due to the merging of two hitherto separate functionalities. The display area is typically backlit because it is used to display information to the user. Ones skilled in the display arts recognize the need to backlight displays in order to better portray the displayed images. However, the input digitizer art area has primarily been focused on how best to capture information being input by a user. Since its primary function is as an input device, it was not considered to be part of a display. As with other types of input devices (e.g., keyboard, mouse, joystick, trackball, etc.), it was left as a passive, unlit device. 
     Unfortunately, because these palmtop computers are intentionally designed to be mobile and portable, they often find use in unlit or poor lighting conditions. It can be quite difficult and frustrating to use a palmtop computer in such darkened or low-light conditions. Due to its perpetually darkened state, there is no visual cue being fed back to the user. Consequently, in these low-light environments, it can be quite challenging or even impossible to input data via the unlit digitizer pad. In many instances, this defeats the purpose of even carrying around a palmtop computers and dramatically lessens their overall usefulness and appeal. Thus, there is a need in the prior art for providing a solution to this problem. 
     SUMMARY OF THE INVENTION 
     The present invention pertains to a method and apparatus for backlighting a handwriting input area for a portable computing device. The portable computing device includes a display area for displaying alphanumeric data and other images. Underneath the display area is a digitizer input area by which users enter handwritten information into the portable computing device. The portable computing device contains handwriting recognition software which converts the handwritten information into alphanumeric data. Both the display area and the digitizer input area are both backlit to facilitate usage in poor lighting conditions. And even under well-lit conditions, it may be more visually appealing, gratifying, and stimulating to backlight the digitizer input area. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is system illustration of a palmtop computer system connected to other computer systems and the Internet via a cradle device. 
     FIG. 2A is a top side perspective view of a palmtop computer system that can be used as a platform for the data entry embodiments of the present invention. 
     FIG. 2B is a bottom side perspective view of the palmtop computer system of FIG.  2 A. 
     FIG. 3 is an exploded view of the components of the palmtop computer system of FIG.  2 A. 
     FIG. 4 is a perspective view of the cradle device for connecting the palmtop computer system to other systems via a communication interface. 
     FIG. 5 is a logical block diagram of the palmtop computer system in accordance with an embodiment of the present invention. 
     FIG. 6 is a front view of a palm top computer system illustrating the display screen, digitizer regions and an exemplary menu in accordance with the present invention. 
     FIG. 7 illustrates a display screen showing a data entry window and a virtual keyboard window and also illustrates a handwriting recognition digitizer on the palmtop computer system in accordance with embodiments the present invention. 
     FIG. 8 shows an exploded objective view of a palmtop computing device having a backlit digitizer including a backlit display and backlit input areas. 
     FIG. 9 shows a side view of the digitizer and lightpipe in accordance with an embodiment of the present invention. 
     FIG. 10 shows an alternative embodiment of the present invention where the digitizer and lightpipe are combined into a single piece. 
     FIG. 11 shows an exploded view of an exemplary module assembly for practicing the present invention. 
     FIG. 12 shows a side view of a palmtop computing device having a backlit digitizer input area. 
     FIG. 13 shows a side view of an alternative embodiment of a palmtop computing device having a backlit digitizer input area. 
     FIG. 14 shows a detailed diagram of an exemplary lightpipe assembly which can be used to practice the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the present invention, a method and system providing improved handwriting recognition for a computer system that backlights a handwriting in put area, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one skilled in the art that the present invention may be practiced without these specific details or with equivalents thereof. 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. 
     NOTATION AND NOMENCLATURE 
     Some portions of the detailed descriptions which follow are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed on computer memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, computer executed step, logic block, process, etc., is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored; transferred, combined, compared, and otherwise manipulated in a computer system. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. 
     It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing terms such as “processing” or “computing” or “translating” or “calculating” or “determining” or “scrolling” or “displaying” or “recognizing” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. 
     NEXT-STROKE PREDICTION IN ACCORDANCE WITH THE PRESENT INVENTION 
     FIG. 1 illustrates a system  50  that can be used in conjunction with the next-stroke prediction data entry system of the present invention. System  50  comprises a host computer system  56  which can either be a desktop unit as shown, or, alternatively, can be a laptop system  58 . Optionally, one or more host computer systems can be used within system  50 . Host computer systems  58  and  56  are shown connected to a communication bus  54 , 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. Optionally, bus  54  can provide communication with the Internet  52  using a number of well known protocols. 
     Importantly, bus  54  is also coupled to a cradle  60  for receiving and initiating communication with a palm top (“palm-sized”) portable computer system  100  of the present invention. Cradle  60  provides an electrical and mechanical communication interface between bus  54  (and anything coupled to bus  54 ) and the computer system  100  for two way communications. Computer system  100  also contains a wireless infrared communication mechanism  64  for sending and receiving information from other devices. 
     FIG. 2A is a perspective illustration of the top face  100   a  of one embodiment of the palmtop computer system of the present invention. The top face  110   a  contains a display screen  105  surrounded by a bezel or cover. A removable stylus  80  is also shown. The display screen  105  is a touch screen able to register contact between the screen and the tip of the stylus  80 . The stylus  80  can be of any material to make contact with the screen  105 . The top face  100   a  also contains one or more dedicated and/or programmable buttons  75  for selecting information and causing the computer system to implement functions. The on/off button  95  is also shown. 
     Importantly, FIG. 2A also illustrates a handwriting recognition pad or “digitizer” containing two regions  106   a  and  106   b.  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. The 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 are typically displayed on the screen  105  for verification and/or modification. 
     FIG. 2B illustrates the bottom side  100   b  of one embodiment of the palmtop computer system of the present invention. An optional extendible antenna  85  is shown and also a battery storage compartment door  90  is shown. A communication interface  108  is also shown. In one embodiment of the present invention, the serial communication interface  108  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, Firewire (IEEE 1394), Ethernet, etc. 
     FIG. 3 is an exploded view of the palmtop computer system  100  in accordance with one implementation. System  100  contains a front cover  210  having an outline of region  106  and holes  75   a  for receiving buttons  75   b.  A flat panel display  105  (both liquid crystal display and touch screen) fits into front cover  210 . Any of a number of display technologies can be used, e.g., LCD, FED, plasma, etc., for the flat panel display  105 . A battery  215  provides electrical power. A contrast adjustment (potentiometer)  220  is also shown. On/off button  95  is shown along with an infrared emitter and detector device  64 . A flex circuit  230  is shown along with a PC board  225  containing electronics and logic (e.g., memory, communication bus, processor, etc.) for implementing computer system functionality. The digitizer pad is also included in PC board  225 . A midframe  235  is shown along with stylus  80 . Position adjustable antenna  85  is shown. 
     A radio receiver/transmitter device  240  is also shown between the midframe and the rear cover  245  of FIG.  3 . The receiver/transmitter device  240  is coupled to the antenna  85  and also coupled to communicate with the PC board  225 . In one implementation the Mobitex wireless communication system is used to provide two way communication between system  100  and other networked computers and/or the Internet via a proxy server. 
     FIG. 4 is a perspective illustration of one embodiment of the cradle  60  for receiving the palmtop computer system  100 . Cradle  60  contains a mechanical and electrical interface  260  for interfacing with serial connection  108  (FIG. 2B) of computer system  100  when system  100  is slid into the cradle  60  in an upright position. Once inserted, button  270  can be pressed to initiate two way communication between system  100  and other computer systems coupled to serial communication  265 . 
     FIG. 5 illustrates circuitry of computer system  100 , some of which can be implemented on PC board  225 . The computer system  100  can be used to perform handwriting recognition processes of the present invention, e.g., process  500  (FIG.  11 A and FIG. 11B) and process  600  (FIG.  12 A and FIG.  12 B). Computer system  100  includes an address/data bus  100  for communicating information, a central processor  101  coupled with the bus for processing information and instructions, a volatile memory  102  (e.g., random access memory RAM) coupled with the bus  100  for storing information and instructions for the central processor  101  and a non-volatile memory  103  (e.g., read only memory ROM) coupled with the bus  100  for storing static information and instructions for the processor  101 . Computer system  110  also includes an optional data storage device  104  (e.g., memory stick) coupled with the bus  100  for storing information and instructions. Device  104  can be removable. As described above, system  100  also contains a display device  105  coupled to the bus  100  for displaying information to the computer user. PC board  225  can contain the processor  101 , the bus  100 , the ROM  103  and the RAM  102 . 
     Also included in computer system  110  of FIG. 5 is an optional alphanumeric input device  106  which in one implementation is a handwriting recognition pad (“digitizer”) having regions  106   a  and  106   b  (FIG.  2 A), for instance. Device  106  can communicate information and command selections to the central processor  101 . System  110  also includes an optional cursor control or directing device  107  coupled to the bus for communicating user input information and command selections to the central processor  101 . In one implementation, device  107  is a touch screen device incorporated with screen  105 . Device  107  is capable of registering a position on the screen  105  where the stylus makes contact. The display device  105  utilized with the computer system  110  may be a liquid crystal device, cathode ray tube (CRT), field emission device (FED, also called flat panel CRT) or other display device suitable for creating graphic images and alphanumeric characters recognizable to the user. In the preferred embodiment, display  105  is a flat panel display. Signal communication device  108 , also coupled to bus  100 , can be a serial port for communicating with the cradle  60 . Device  108  can also include an infrared communication port. 
     FIG. 6 is a front view of the palmtop computer system  100  with a menu bar  305  open displaying a pull down window. Also shown are two regions of digitizer  106   a  and  106   b.  Region  106   a  is for receiving user stroke data for alphabet characters, and typically not numeric characters, and region  106   b  is for receiving user stroke data for numeric data, and typically not for alphabetic characters. In the currently preferred embodiment of the present invention, these two digitizer regions  106   a  and  106   b  are backlit. In other words, lighting is provided to shine through these two regions. Physical buttons  75  are also shown. In one embodiment, these physical buttons  75  are also backlit. Although different regions are shown for alphabetic and numeric characters, the present invention is also operable within a single region that recognizes both alphabetic and numeric characters. Again, such a combined region would be backlit. Furthermore, artwork  320  and  325  can also be backlit. 
     FIG. 7 is a front view of the palmtop computer system  100  with several display windows open on screen  105  including a virtual keyboard window  315 . The user has the choice of displaying a virtual keyboard image on display  105  and entering characters by selecting one of the displayed characters of the virtual keyboard image. Window  310  is part of a generic application program executing on system  100 . Window  310  is a data entry window in that the application program is requesting information to be entered by a user. The information requested and the application program could be any information and any program. Typically, data entry window  310  has at least one data entry field  312  for accepting character data therein. When not entering data using the virtual keyboard  315 , the user can stroke a character within pad  106  (either region  106   a  or  106   b ). The recognized character is then also placed into the displayed data entry field for user verification and use. This process can be repeated. It is appreciated that the digitizer regions  106   a  and  106   b  is separate from the display screen  105  and therefore does not consume any display area. In the currently preferred embodiment, the data entry window  310 , virtual keyboard screen  315 , stroke recognition region  106   a,  and numeric entry region  106   b  are all backlit. Furthermore, keys  75  can also be backlit. 
     FIG. 8 shows an exploded objective view of a palmtop computing device having a backlit digitizer including a backlit display and backlit input areas. The display area displays information to the user. The input area is sometimes referred to as the “graffiti” area. This area is used to input handwritten information (e.g., via a stylus). In this embodiment, the digitizer  801  is overlaid on top of a lightpipe  803 . Lightpipe  803  is a rectangular piece of material used to conduct light. Lightpipe  803  is approximately the same size, shape, and form factor as that of the digitizer  801 . Lightpipe  803  is used to conduct the light from a lightsource  802  and reflect that light evenly upwards through the transparent digitizer  801 . Light source  302  can be a light emitting diode (LED) or a cold cathode fluorescent light (CCFL). Light shining from light source  802  is reflected via a series of sawtoothed indentations of lightpipe  803  such that the light is evenly distributed to backlight the digitizer  801 . It should be noted that the light source  802  can be placed on any of the four sides of the lightpipe  803 . 
     FIG. 9 shows a side view of the digitizer  801  and lightpipe  802 . It can be seen that the digitizer  801  is overlaid on top of the lightpipe  802 . Thereby, light reflects from lightpipe  802  and emanates through the digitizer  801 . Characters, artwork, or other types of images are thereby backlit by the light shining from the lightpipe  802  through digitizer  801 . 
     FIG. 10 shows an alternative embodiment of the present invention. In this embodiment, the digitizer and lightpipe are combined as a single piece  1004 . The light source  1001  is used to provide light to the combined digitizer/lightpipe  1004 . One or more films, coatings, and/or coverings  1003  can be overlaid on top of the digitizer/lightpipe  1004 . A touch panel spacer  1002  is used to separate the film  1003  from the digitizer/lightpipe  1004 . This embodiment is preferable because it reduces the overall thickness of the palmtop computing device. 
     FIG. 11 shows an exploded view of an exemplary module for practicing the present invention. The module assembly is comprised of a touch panel  1101  as the top-most layer. Residing underneath the touch panel  1101  is a bezel  1102 . A printed circuit board containing the semiconductor chips and other electronic components is shown as  1103 . Next, a LCD panel  1104  is used for display purposes. Finally, a backlight element  1105  is used to provide the backlighting. In one embodiment, the backlight element  1105  is comprised of an electro-luminescent (EL) material. The backlight element  1105  extends to cover both the display area as well as the input digitizer area(s). The backlight element  1105  can also be extended to cover any other areas, such as keys, logos, artwork, jacks, plugs, adapters, interfaces, menus, prompts, icons, security features, etc. 
     FIG. 12 shows a side view of a palmtop computing device having a backlit digitizer input area. The digitizer layer is shown as  1201 . This digitizer layer includes both a display area as well as an area whereby the user inputs handwritten information (e.g., alphanumeric). A graphics layer  1202  is used to provide any graphics which the manufacturer desires to display to the user. Next, a display layer  1203  is used to display information to the user. Underneath the display layer  1203  is the backlight layer  1204 . The backlight layer  1204  can be a lightpipe to an electroluminescent (EL) layer. Furthermore, backlight layer  1204  can be fashioned from a single piece and bent to conform to the requisite form factor (as shown by the dashed lines), or it can be fashioned as two separate pieces. A separate backlighting piece  1205  can be dedicated to backlight the input digitizer area (e.g., the graffiti area). 
     FIG. 13 shows a side view of an alternative embodiment of a palmtop computing device having a backlit digitizer input area. In this embodiment, the various layers are arranged in a different configuration. The digitizer layer  1301  is the top-most layer. However, the graphics layer  1302  resides directly underneath the digitizer layer  1301 . Next comes the backlighting layer  1303 . Backlighting layer  1303  extends the full length of the digitizer layer  1301 . Thereby, backlighting is provided to the display as well as input areas, including the handwriting recognition area. A light source  1305 , such as a LED or CCFL can be used. In one embodiment different or contrasting colors can be used to provide the background lighting. For example one color can be used for the display area whereas a different color can highlight the input area. Alternatively, different light intensities for display as well as backlighting can be provided for select areas viewable by the user. It should be noted that there exist any number of different ways by which the present invention may be physically implemented. 
     FIG. 14 shows a detailed diagram of an exemplary lightpipe assembly which may be used to practice the present invention. The actual lightpipe is shown as a rectangular piece of material  1401 . The lightpipe  1401  is optically coupled to receive light from a phosphorous light pipe corridor  1402 . In turn, the phosphorous light pipe corridor  1402  derives its lighting from LEDs  1403 . An LED printed circuit board  1404  is used to drive the LEDs  1403 . A similar LED and LED PCB arrangement is found at the opposite end of the lightpipe corridor  1402 . Lastly, a connector  1404  electrically connects the lightpipe assembly to the display driver board. 
     Therefore, a method and apparatus for the backlighting of a digitized input area for portable computing devices has been disclosed. 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 below claims.