Electronic Timepiece Hand Position Detection and Correction
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Solution Overview
Problem
Electronic timepieces equipped with hand position detecting mechanisms face issues such as failure to detect positional shifts of the second hand for extended periods, excessive power consumption due to frequent detection, and inability to accurately correct hand position counters when hands are abnormally stopped by external factors like strong magnets.
Innovation Solution
An electronic timepiece design that includes a rotating body with a target section, a detection section, and a detection control system operating every rotation period to detect the target section's presence and absence, allowing for efficient hand position detection and correction of hand position counters without counting abnormal stop times, using a counted value holding and correcting mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hand position detection is executed every second or every two seconds to detect positional shift of the second hand, then detection responsiveness is improved, but power consumption becomes excessive
Solution Approach 1:
The detection control section executes hand position detection periodically at specific intervals (e.g., every second or every two seconds) rather than continuously, which reduces power consumption while still maintaining adequate detection responsiveness for positional shifts of the second hand
2Use of energy by moving object
If hand position detection is executed only at the timing when penetration holes of gears appear at the detection position, then power consumption is reduced, but detection capability is lost when hands are stopped at the detection position due to external factors
Solution Approach 1:
A rotating body with a target section is introduced as an intermediary detection target. The detection section detects the target section on the rotating body at specific timings (when it appears and disappears at the detection position), which serves as a reliable indicator of hand position without being affected by whether the hands are moving or stopped due to external factors
3Measurement precision
If the number of times of detection of hand stops is counted to correct hand position counter value, then correction accuracy is improved, but a large bit counter is required when abnormal stop extends over long period
Solution Approach 1:
The invention extracts only the necessary correction information (hand position counter value at abnormal stop detection) without continuously counting the number of times of hand stop detection. This approach maintains correction accuracy while avoiding the need for large bit counters that would be required to count extended abnormal stop periods
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 rapid detection of positional shifts and abnormal stops, reduces power consumption, and allows for accurate correction of hand position counters without the need for large bit counters, ensuring reliable timekeeping even when exposed to strong magnets.
Implementation Method 1
detecting light passing through the penetration holes with a photodetector
Data Source
AI summary
Disclosed is an electronic timepiece, comprising: a second hand and a minute hand; a stepping motor which performs a stepping drive of the hands; a rotating body which includes a target section, and rotates with the second hand; a detection section which detects an existence of the target section; a detection control section which makes the detection section operate by every rotation period, to make the detection section detect the existence of the target section at a first timing and at a second timing; a hand position counter which counts estimated positions of the hands based on the number of drive times of the stepping motor; a counted value holding section capable of temporarily holding a value of the hand position counter; a counted value saving section which makes the counted value holding section hold the value; and a counted value correcting section which corrects the value.