Electronic Timepiece Hand Detection Using Transient Photocurrent
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Solution Overview
Problem
Existing hand position detection methods in analog timepieces consume excessive power and may inaccurately determine the position of hands due to the reliance on stable current outputs from light-receiving elements.
Innovation Solution
The method involves applying voltage to a detector after light passes through wheel holes, utilizing parasitic capacity to amplify current output by transient response, and determining hand position based on a threshold before the current reaches a steady state, reducing power consumption and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage is applied to the light-receiving element before illuminating the light-emitting element, then the current output can be measured in steady state, but the power consumption increases and detection accuracy decreases
Solution Approach 1:
The light-emitting element is illuminated in advance before voltage is applied to the light-receiving element. This preliminary illumination ensures that when voltage is applied, the current output immediately reflects the hand position without requiring a steady-state period, thereby reducing power consumption while maintaining detection accuracy.
Solution Approach 2:
The patent transitions from a static measurement approach (waiting for steady state) to a dynamic approach (measuring transient current response). By detecting the current output during the transient period before steady state is reached, the system achieves accurate hand position detection with reduced power consumption.
2Stability of the object's composition
If the current output is measured in steady state, then stable measurement is achieved, but power consumption increases
Solution Approach 1:
The light-emitting element is illuminated in advance before voltage is applied to the light-receiving element. This preliminary action ensures that the optical path is already established and the hand position is captured in the transient current response, eliminating the need for prolonged steady-state measurement and reducing power consumption.
Solution Approach 2:
The patent skips the traditional steady-state waiting period by directly measuring the current output during the transient response phase. This rushing through the initial transient period allows accurate detection without the power consumption penalty of maintaining steady-state conditions.
3Use of energy by moving object
If the light-emitting element is illuminated after voltage is applied to the light-receiving element, then power consumption is reduced, but detection accuracy decreases due to unstable current output
Solution Approach 1:
The light-emitting element is illuminated in advance before voltage is applied to the light-receiving element. This ensures that when voltage is applied, the current output immediately contains accurate hand position information, eliminating the need for steady-state stabilization and enabling accurate detection with reduced power consumption.
Solution Approach 2:
The patent inverts the conventional sequence of operations: instead of applying voltage first and then illuminating, it illuminates first and then applies voltage. This inversion captures the hand position information in the transient current response, achieving both low power consumption and high detection accuracy.
4Reliability
If steady-state current measurement is used, then stable detection is achieved, but the detection time increases
Solution Approach 1:
The patent rushes through the transient period by directly measuring the current output immediately after voltage application, skipping the traditional steady-state waiting period. This approach achieves reliable hand position detection significantly faster than conventional methods.
Solution Approach 2:
The preliminary illumination of the light-emitting element ensures that the optical path is established before voltage application, so the transient current response contains complete hand position information, enabling fast and reliable detection without steady-state stabilization time.
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
This approach reduces power consumption and enhances hand position detection accuracy by utilizing transient response to amplify current values, allowing for precise determination of hand positions with reduced power usage.
Implementation Method 1
a detector corresponding to the wheel, the detector being configured to detect light that passes through the hole of the wheel in response to voltage being applied to the detector and configured to output current corresponding to an intensity of the detected light
Data Source
Figure 1~2
Figure 3A~3D
Figure 4~5
AI summary
An electronic timepiece (100) includes: a hand (3); a wheel (31) corresponding to the hand and having a hole (310); a detector (5) corresponding to the wheel, the detector being configured to detect light (L1, L2) that passes through the hole of the wheel in response to voltage being applied to the detector and configured to output current corresponding to an intensity of the detected light; and a processor (20). The processor obtains, at a predetermined timing (A3, B2), a current-based value that is based on the current output by the detector. The processor determines whether or not the current-based value is greater than or equal to a predetermined threshold. Based on the determination, the processor performs position detection of the hand. The predetermined timing is earlier than a timing at which the current-based value, which is based on the current output by the detector, becomes a value in a steady state.