This invention relates generally to an electronic timepiece adapted to provide standard timekeeping and/or chronographic display of time and especially to an electronic wristwatch having a chronographic display including indicating means for indicating the chronographic function selected.
While chronographic wristwatches having stopwatch and measuring capabilities which also include timekeeping displays have taken on various forms, such wristwatches have been found to have various defects during normal operation. Particularly, when such chronographic wristwatches are mechanical and are used as a stopwatch, the hour and minute hands for displaying time are usually indistinguishable from those used for the stopwatch function. Moreover, because it is necessary to use the second hand as a stopwatch hand the accurate measuring of seconds during normal timekeeping cannot be maintained. Also, it is extremely difficult to measure exact time periods to units less than a second because of the small displacement of the second hand.
Many of these problems can be overcome by wristwatches having a single digital display and separate chronographic divider and timekeeping divider circuits, the chronographic divider circuits providing for chronographic accuracy to tenths and hundredths of seconds which is unobtainable in mechanical watches. Moreover, because separate divider circuits are utilized the information necessary for an accurate second display is in no way affected by the use of the wristwatch as a chronograph. However, such wristwatches which incorporate a timekeeping and chronographic capability suffer from certain drawbacks in circuit complexity and chronographic operation. Specifically, during chronographic operation it is impossible to distinguish between when the display has been stopped because of a start-stop operation and when the display has been stopped during a lap operation wherein the lap time is displayed but the chronographic divider circuit continues to count.
USPTO Backgrounds
USPTO Backgrounds