This paper studies airflow damping of microoscillators to establish a design method for information and sensing devices that use microactuators. First, a simple and approximate formula of damping ratio is derived by using a solution of Stokes equation for a oscillating cylinder boundary condition. Then relationships between damping ratio and oscillator size are clarified by using the derived formula for silicon and iron oscillators. Finally the analytical results are compared with experimental ones to show the validity of the proposed theory.

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The improvement of the degree of high precision step for the solar watch has been done successfully. Out of which the significantly improved 2 points shall be highlighted as follows. The one is the circuit system to hold a degree of a high precision step in the wide voltage range; not only a regulator, which drives a crystal-controlled oscillator circuit, and a temperature sensor circuit to have done it since before but also you must reduce the influence of the change in the junction capacitance of protection diode of the connection terminal for the crystal vibration. The other is the circuit system which does the slight adjustment of a degree of a step without opening a reverse side cap; the step occasion data changed into the magnetic signal by the outside device are detected by using the coil for the motor, and those data are written in the unvolatility memory.

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In the optimum design of stepping motors, it is important to solve the accurate characteristics of them. However, it is difficult to obtain the characteristics by the experiment method because of small size. So we have tried to obtain the characteristics by the magnetic field analysis method. Last year, we have analyzed the cogging torque, static stability position and leakage of magnetic flux of a stepping motor by use of the 2-D and 3-D static magnetic fields analysis, and confirmed practical use method and effectiveness of these analysis. In this paper, we analyze the 3-D dynamic transient characteristic of the stepping motor excited from drive pulse voltage source and compare the calculated result with the measured result. The usefulness of understanding the characteristic of the stepping motor by the dynamic magnetic fields analysis is confirmed.

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Various watches, each having a calendar mechanism, have been developed and produced on commercial basis, following the technique which has been cultivated through the age of the mechanical watch. In the conventional calendar mechanism, such a mechanism in which the date dial driven by a date dial driving wheel is general. However, in the calendar watch, it is necessary to correct the date at the end of the even month. On the other hand, a month-end no-correction watch is produced, in which the correction is realized by controlling a microcomputer IC and a calendar-exclusive gear train having a Geneva stop, using a logic circuit. However, in the mechanism, there are a backlash between the toothed portion of the date dial and the date dial driving portion, and a clearance in the Geneva stop, which may cause the chattering of the date dial and the deviation of the date indication from the date window. Therefore, aiming to mount on the 98-model of "The Citizen" pursuing a watch function based on the user principle, a calendar mechanism is developed, whereby the user is released from the trouble to correct the date at the even month and the leap year, maintaining the ease of use of the conventional analogue watch, and the chattering of the date dial, caused by the backlash and the clearance at the date dial driving portion which occurs when the date dial is driven by the calendar-exclusive gear train, does not generate, and the deviation of the date indication is obviated.

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Seiko Instruments Inc.watch design department introduced 3 dimensions CAD(U-Graph)in 1994, and began to use it for the movement design. This time we used 3 dimensions CAD from plan design stage of the new Chronograph(Cal.6S74A). And we did the structure analysis, mechanism analysis and clearance analysis of all the parts. We could develop this complicated watch in about the half of the usual development period.

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