JPS5472994A - Crystal vibrator for electronic wristwatch - Google Patents

Abstract

PURPOSE:To make zero-temperature coefficient temperature (TP) of a frequency rise without changing present dimentions, by making a tuning-fork crystal vibrator vibrate in a higher-order mode. CONSTITUTION:At the time of obtaining flat frequency-temperature characteristics over broad range by connecting two tunig-fork crystal vibrators different in TP in parallel to one oscillator circuit, electrodes 9c, 9e, 9g, 9j, 9l, and 9n provided to, for example, vibrating arms 9a and 9b are connected in sequence into one electrode, electrodes 9d, 9f, 9h, 9i, 9k, and 9m are also connected into the other electrode, and l'' is made equal to 0.22l, so that the secondary high-frequency excitation can be made possible in vibration state 8a at vibration contact 8b with l'= 0.22l. In this case the frequency becomes about six times as high as that of the fundamental vibration and as to the vibrator of W in vibrating-arm width and l in length, W/l becomes about twice and a half as high as that of the fundamental vibration so as to make a about-20 deg.C-rise in TP possible, so that the flat frequency temperature range will be extended without changing the size of the vibrator.