Electronic Timepiece Hand Position Detection via Dynamic Timing
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Solution Overview
Problem
Conventional hand position detecting devices for electronic timepieces fail to accurately detect the position of hands when assembling errors occur, leading to incorrect recognition and precise alignment of the center hand, especially due to variations in timing caused by minute hand displacements.
Innovation Solution
A hand position detecting device that uses a second hand wheel with through holes arranged in specific patterns across angular segments, allowing for accurate detection and correction of hand positions by adjusting the examination timing based on assembling errors, ensuring consistent detection patterns regardless of minute hand displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional hand position detecting device uses a fixed detection timing based on through hole overlap, then the detection process is simple, but the detection accuracy deteriorates when assembling errors occur in the minute hand
Solution Approach 1:
The detection timing is made dynamic by adjusting it based on the detected minute hand position. Instead of using a fixed detection timing, the system determines the optimal detection timing by detecting the through hole of the minute hand wheel and calculating the appropriate time to detect the second hand wheel through hole, thereby compensating for assembling errors in the minute hand.
Solution Approach 2:
The detection timing parameter is changed based on the minute hand position. The system varies the detection timing parameter according to the detected minute hand through hole position, allowing accurate second hand detection despite variations in minute hand assembly precision.
2Productivity
If the minute hand is assembled with displacement, then the hands mounting process is faster, but the hand position accuracy deteriorates
Solution Approach 1:
The system uses feedback from the minute hand position detection to adjust the second hand detection timing. By detecting the through hole position of the minute hand wheel and using this information to determine when to detect the second hand wheel, the system compensates for assembly displacements without requiring precise manual alignment.
Solution Approach 2:
The detection system automatically compensates for assembly errors by using the minute hand position information itself to determine the appropriate detection timing. The system serves itself by using its own detection capabilities to correct for manufacturing variations.
3Measurement precision
If the detection timing is adjusted to compensate for minute hand displacement, then the hand position detection accuracy improves, but the detection algorithm complexity increases
Solution Approach 1:
The system performs preliminary detection of the minute hand through hole position before determining the second hand detection timing. This preliminary action allows the system to pre-calculate the appropriate detection timing based on the minute hand position, ensuring accurate second hand detection while maintaining a relatively simple algorithm structure.
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
Enables precise detection and correction of hand positions, preventing wrong recognition and ensuring accurate alignment of hands even with assembling errors, by using a second hand wheel with unique hole patterns and adjusting examination timing, thus improving the reliability of hand position detection in electronic timepieces.
Implementation Method 1
a light emitting unit for emitting light, and a photosensor for receiving the light emitted by the light emitting unit
Data Source
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AI summary
A hand position detecting device including: a first gear rotating with a minute hand; a second gear rotating with a second hand; a first detection target portion that is provided on the first gear and identifiable by light irradiation; a second detection target portion that is provided on the second gear and identifiable by light irradiation; and a detector, wherein the second detection target portion is formed to be divided into a plurality of parts over a predetermined angular range out of a center angle of 360° of the secondgear, andapresence-or-absence pattern of the second detection target portion in an angular range of successive N (N represents one of 5 to 10) angular segments with any angular segment being set as a start point is made different when the angular segment of the start point is different.