Electronic Timepiece Sub-Dial Hand Control for Faster Chronograph Switching
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Solution Overview
Problem
Existing electronic timepieces with a chronograph mode require the hour hand of a sub-dial to move a maximum of 12 hours to return to the zero position, taking an excessive amount of time when switching to the chronograph mode.
Innovation Solution
The electronic timepiece includes a display control section that distinguishes between two indicating positions for the first indicating hand, allowing it to be moved to a measurement start position with a shorter movement time by fast forwarding based on mode switching operations, utilizing a two-coil step motor for the sub-dial hands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the hour hand of the sub-dial is moved to the zero return position by conventional rotation when switching to chronograph mode, then the hand reaches the correct position, but the movement time is excessively long (up to 12 hours)
Solution Approach 1:
The patent applies dynamics by enabling the hour hand to switch between two distinct movement states: conventional slow rotation for normal timekeeping and fast forwarding for rapid position adjustment during mode switching. The control section dynamically selects the appropriate movement mode based on the operational context, allowing the hand to accelerate to high speeds when returning to the zero position in chronograph mode, thereby dramatically reducing the time required for position adjustment while maintaining normal rotational characteristics during standard operation
2Device complexity
If the hour hand is always moved clockwise to the zero return position, then the movement direction is simple to control, but the movement time may be maximized when the hand is near the zero position
Solution Approach 1:
The patent applies inversion by allowing the hour hand to rotate in both clockwise and counterclockwise directions depending on its current position. When switching to chronograph mode, the control section determines whether to move the hand clockwise or counterclockwise based on which path requires fewer steps to reach the zero return position. This bidirectional approach reverses the conventional unidirectional control logic, enabling the system to minimize movement time by selecting the optimal rotation direction rather than always following a fixed clockwise path
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the hour hand to reach the zero return position in a significantly reduced time, typically within 3.5 seconds, enhancing user convenience and clarity in mode transitions.
Implementation Method 1
utilizing a two-coil step motor for the sub-dial hands
Data Source
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AI summary
An electronic timepiece includes a first operation section configured to perform a mode switching operation for switching between a time display mode and a chronograph mode, a first indicating hand configured to display an hour of a time in a 12-hours system in the time display mode and display an hour of a measurement time in the chronograph mode, and a display control section configured to move the first indicating hand to a measurement start position in the chronograph mode by fast forwarding based on the mode switching operation for switching to the chronograph mode, in which the display control section is configured to distinguish and manage each of indicating position of 0 o'clock and 12 o'clock and set, when switching to the chronograph mode, an indicating position having a shorter movement time of the first indicating hand among two indicating positions to the measurement start position, based on a display time of the first indicating hand at a time of the switching operation, and move the first indicating hand to the set measurement start position.