Abstract:
An electronic date calculator includes an electronic processor, input keys operably connected to the processor, at least one date function key corresponding with a selected date unit and operably connected to the processor, and a display operably connected to the processor. The processor is programmed to drive the display to show a present date. In response solely to entry of a multiplier from the input keys and a date unit from the date function key, the processor adds a product of the selected date unit and the multiplier to the present date to generate a resulting date, and drives the first display to show the resulting date.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Provisional Application No. 60/940,512 Filed May 29, 2007. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates generally to electronic calendars and more particularly to an electronic calendar with date calculation functions. 
         [0003]    Various types of electronic calendars and timepieces are known which can track and display the present date. Calculators and computers are also available which can display the present date, and can perform calculations using dates. 
         [0004]    In various situations it is desirable to know the exact value of a date which is a certain interval in the future or the past, i.e. a certain number of days, weeks, or months ahead of or prior to the present time. For example, it may be desired to schedule a business meeting, medical appointment, bill payment, business action item, or the like to occur 30 days, two weeks, or six months from the present day. Normally, determination of the future date would involve laborious manual counting of days and/or reference to several pages of a calendar. It is possible using known computer techniques to make such calculations using a conventional handheld calculator or microcomputer. However, these calculations typically require several keystrokes to select the date calculation function and enter the proper arguments, or in the case of a computer, a spreadsheet formula entry or quasi-programming entry is required. These functions are thus slow and inconvenient. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    These and other shortcomings of the prior art are addressed by the present invention, which provides a date calculator that provides convenient calculation and display of future and past dates. 
         [0006]    According to one aspect of the invention, a date calculator includes: an electronic processor; input keys operably connected to the processor; at least one date function key corresponding with a selected date unit and operably connected to the processor; and a first display operably connected to the processor. The processor is programmed to: (a) drive the first display to show a present date, and in response solely to entry of a multiplier from the input keys and a date unit from the date function key: (b) multiply the selected date unit by the multiplier, and add the product thereof to the present date to generate a resulting date; and (c) drive the first display to show the resulting date. 
         [0007]    According to another aspect of the invention, a method of calculating a date includes: using an electronic processor, determining a present date and showing the present date on a display; inputting a multiplier to the processor; using a single date function key operably connected to the processor, inputting a date unit to the processor; in response to the input of the date unit, using the processor to add the product of the multiplier and the interval to the present date, so as to obtain a resulting date; and showing the resulting date on the display. 
         [0008]    According to another aspect of the invention, a computer program product includes a computer-readable medium containing instructions causing a computer to carry out a method of calculating a date. The method includes: determining a present date and showing the present date on a display operably connected to the computer; receiving an input of a multiplier; showing on the display at least one date function key, the date function key bearing indicia representing a preselected date unit; in response to the input of the date unit by the at least one date function key, adding the product of the multiplier and the interval to the present date, so as to obtain a resulting date; and showing the resulting date on the display. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which: 
           [0010]      FIG. 1  is a front view of a date calculator constructed according to an aspect of the present invention; 
           [0011]      FIG. 2  is a schematic view of the internal arrangement of the date calculator of  FIG. 1 ; 
           [0012]      FIG. 3  is block diagram illustrating the method of operation of the date calculator; 
           [0013]      FIG. 4  is a front view of the date calculator of  FIG. 1  after a first user input; 
           [0014]      FIG. 5  is a front view of the date calculator of  FIG. 1  with a future date displayed; 
           [0015]      FIG. 6  is a front view of an alternative date calculator; and 
           [0016]      FIG. 7  is a schematic view of a date calculator as implemented on a general-purpose computer. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,  FIG. 1  depicts an exemplary date calculator  10  constructed according to an aspect of the present invention. It is similar in construction to a prior art hand calculator and includes a housing  12 , a date display  14 , numeric keys  16 , date setting keys  18 , and date function keys  20 . In the illustrated example there are three date function keys  20  which are labeled “D” for days, “W” for weeks, and “M” for months, respectively. 
         [0018]    As shown here, the date calculator  10  also incorporates the functions of a conventional mathematical calculator and includes a numeric display  22  and mathematical function keys  24  used to enter arguments and commands and to display results of mathematical operations. The principle of the present invention may be incorporated in any type of electronic device that has a date display including, for example, watches or alarm clocks, hand or desk calculators, stand-alone calendar units, desk planners, or the like. 
         [0019]      FIG. 2  shows one possible internal arrangement of the date calculator  10 . A microprocessor  26  of a known type is mounted to a circuit board  28  along with the displays  14  and  22  (For example LCDs) and switch banks  30  which underlie the keys. The components are operably connected to each other, for example by conductive traces  32  on the circuit board  28 . The microprocessor  26  includes a quartz clock, real-time clock (RTC) chip or other suitable time reference. The date calculator  10  is provided with a power source such as the illustrated battery  34 , line current, photovoltaic cells, or combinations thereof. Other known types of processors, circuits, or computers capable of executing date calculations may be substituted for these components. The microprocessor  26  or other calculating device may execute stored software instructions to perform the operations described below, or those functions may be incorporated as a part of its permanent circuit configuration (i.e. it may be a single-purpose device). 
         [0020]    The operation of the date calculator  10  is now described with reference to  FIG. 3 . When initially started, the date setting keys  18  or other suitable means are used to set the present date in the same manner as a prior art electronic calendar. Thereafter, in a nominal state, the date display  14 , driven by the microprocessor  26 , will show the present date (block  200 ). In  FIG. 1 , the example date shown is May 14, 2007 on the Gregorian calendar with a month/day/year format. When the user desires to calculate a future date, he first enters a multiplier using the numeric keys  16  at block  202 . In the example shown in  FIG. 4 , the user has entered the sequence 1, 0. The result “10” shows on the numeric display  22 . It is noted that, if a simpler interface is desired, other kinds of input keys could be substituted for the numeric keys  16 . For example, simple keys (not shown) which increment a digit in the numeric display  22  each time they are pushed, and then cycle back to zero after reaching an upper limit, could be used. Then, at block  204 , the user presses the date function key  20  with the selected unit. In this case, the user has pressed the key labeled “D” for days. Once the date function key  20  is pressed, a date calculation routine is immediately called at block  206  with the selected multiplier and the unit as arguments. 
         [0021]    The microprocessor  26  adds an interval, which is defined as the number of units equal to the multiplier (i.e. the product of the unit and the multiplier), to the present date. In this case the calculated interval would be 10 days. The resulting sum is converted to the resulting or future date. As shown in  FIG. 5 , the future date would be May 24, 2007 on the Gregorian calendar, or May 24, 2007 in the illustrated format. This date is shown on the date display  14  at block  208 . After a suitable selected delay at block  210 , for example about 30 seconds, the date display  14  reverts to the present date. Alternatively, the future date may be displayed until a specified key or key sequence is entered. 
         [0022]    It is also possible to use the date calculator  10  to calculate a date in the past. For example, the minus or “negative” key  25  provided as part of the mathematical function keys  24  may be pressed before or after the entry of the multiplier as described above. The subsequent processing would then proceed as outlined above, except that the interval added to the present date would be a negative interval (this could also be conceptualized as subtracting an interval from the present date), and the resulting date displayed would be the selected number of days, weeks, months, etc. in the past. 
         [0023]    Various methods may be used to perform the actual date calculation. In most cases, the present date will be stored in the microprocessor  26  as an integer (i.e. a serial date). This value is converted to an easily human-readable format (i.e. Gregorian calendar) for display in accordance with known methods. The addition of the date interval to the present date the present date is also carried out using known programming and/or software methods, for example a “dateadd” programming function. 
         [0024]    In addition to the functions described above, the date calculator  10  may be extended to add other intervals to the present time by providing additional date function keys  20 . For example, keys for years or decades might be added if desired. Furthermore, the time of day may be part of the calculation as well as the date. For example,  FIG. 6  illustrates an alternative date calculator  110  which also displays the time in its date display  114 . The date function keys  120  include additional units such as seconds, minutes, and hours. In a process similar to that described above, a selected amount of time may be added to the present date and time and the date calculator  110  would display the future date and time. For example, if 24 hours were added to the date and time of May 14, 2007 12:01 PM, the resulting future date and time displayed would be May 15, 2007 at 12:01 PM. 
         [0025]    While the above description has described a hardware device, it will be understood that the present invention may also be implemented as software. For example,  FIG. 7  illustrates a general-purpose computer  150  of a known type, such as a PC-compatible or MACINTOSH computer, with a monitor  152 . The computer  150  is programmed with software code which causes it to display an image of a date calculator  210 . The image  210  has an interface similar to the date calculator  10  described above and includes, at a minimum, a date display  214 , and graphical user-operable software “buttons” representing date function keys  220 . In the illustrated example there are three date function keys  220  which are labeled “D” for days, “W” for weeks, and “M” for months, respectively. A numeric keypad  154  of the computer  150  may be used for number entry in place of the numeric keys described above. If desired, the image  210  may be designed to imitate the physical appearance of a hand-held calculator. 
         [0026]    The operation of the software to calculate a resulting date based on a unit and multiplier is substantially identical to the operation of the date calculator  10  described above, with the key difference being that the user interacts with the graphical buttons of the image  210  using a pointing device in a known manner, rather than physical hardware. Touch-screen buttons could also be used. Optionally, the image  210  may be accessed by a software “shortcut” or icon, and the software may be programmed to remove the image from the screen automatically after a preselected time. Furthermore, the software may include a user-selectable parameter for setting any desired date as the present date or “base date” for calculations. 
         [0027]    The foregoing has described a date calculator. While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention. Accordingly, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only.