European mechanical Clock came to Japan while end of Muromachi period. This Clock was developed as Japanese unique Clock (Wa-dokei) which has old Japanese way of time counting. Furthermore inside mechanism of Clock has been transferred to Karakuri Ningyo (Mechanical Doll) which is for people's entertainment in peaceful Edo Period. The author investigated and researched mainly technology transfer of units of escapements and governors from Clock to Karakuri Ningyo.
We developed the solar powered watch of the free dial design that placed a ring-shaped solar cell in the case side. We designed it from the experiments such as the light receiving efficiency by the posture difference, illuminance distribution in the solar cell, the shape of the transmissive ring. Furthermore we demonstrated that enough balance was provided from data by the actual use of this new concept solar watch.
The "PROTREK" is the wrist watch series that CASIO has been producing for outdoor use which has advanced sensor technologies to measure various data. We proudly announce the newly developed analog wrist watch PROTREK PRX-7000T. This analog wrist watch is an atomic watch with solar powered and with three sensors to measure atmospheric pressure for altimeter and barometer, magnetic field for compass and temperature for thermometer. PRX-7000T is targeted to develop as a practical tool with the high visibility even at 8,000 meters altitude peaks in the Himalayan Mountains. This paper explains the technical summary of the development of PRX-7000T.
We report two key points about development of active-matrix EPD watch. The first point is to improve display response on user operation. We found that it is enough for reading menu or time on the screen to drive at least 90% of saturated white reflectance. The other is how to ensure display quality to drive a part of screen in the long term. We decided to select suitable EP sheet lot to use trough testing reflectance-writing times.