In 2018, CITIZEN Watch Co., Ltd. released the Eco-Drive Satellite Wave GPS F990 watch that receives time signal information from artificial satellites and corrects displaying time and date accurately. This paper describes Twin Coil Motor with Forward/Reverse High-Speed Drive System mounted on the F990. This is a new stepping motor system that enables high speed by driving 2-steps collectively and monitoring the rotation of the motor. We succeeded in doubling the rotational speed of the hour hand and minute hand than former products.
In a multifunction timepiece, the size of a product generally increases with an increase in functions. On the other hand, there is also a certain demand for smaller and thinner products. Therefore, this time, focusing on miniaturization of wristwatches, we have developed an analog watch equipped with Bluetooth® communication function and radio wave solar function that are both thin and functional.
We developed the GPS solar watch Astron (Cal. 7X) in 2012, inheriting the name of the quartz watch "Astron". On going quest for the power reduction, down-sizing, and usability-improvement, the second genaration GPS solar Astron (Cal. 8X) and the third generation (Cal. 5X) were developed. Cal. 5X achieved the size and usability for a long-time use. In this report, we explain the following three feature technology developed in Cal. 5X: (1) power reduction and receiving performance improvement of GPS-IC, (2) size reduction technology, and (3) improvement of automatic GPS time synchronization.