Watch Hand Position Detection With Dual Light-Limiting Sensors
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Solution Overview
Problem
Conventional timepieces face challenges in accurately detecting the position of pointing hands due to the inability to prevent light from oblique angles, leading to inaccurate hand position detection in varying illuminance environments.
Innovation Solution
The timepiece incorporates a first light detector and a second light detector, along with mechanisms to limit the amount of external light detected by each, using through holes and different structures to ensure perpendicular light detection, thereby enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional timepieces use external light for hand position detection without light limiting mechanisms, then the device complexity is low, but the measurement precision of hand position detection deteriorates due to oblique light interference
Solution Approach 1:
The patent introduces light limiting mechanisms (such as light shields or apertures) as intermediary elements between the external light source and the light receiving element. These intermediaries selectively block oblique light while allowing perpendicular light to pass through, thereby improving detection accuracy without requiring complex active control systems. The light limiting mechanism acts as a passive optical filter that mediates the interaction between external light and the detection system.
2Measurement precision
If the timepiece uses a single light limiting mechanism for both hand position detection and illuminance detection, then the device complexity is reduced, but the measurement precision of both functions deteriorates due to inability to detect only perpendicular light
Solution Approach 1:
The patent divides the light detection system into separate functional segments: one light limiting mechanism for hand position detection and another for illuminance detection. Each segment is optimized for its specific function, with light receiving elements positioned and configured to detect light characteristics relevant to their respective measurement purposes. This segmentation allows both functions to achieve high precision independently without interfering with each other.
Solution Approach 2:
The patent applies different light limiting structures and detection configurations tailored to specific detection locations and requirements. The light limiting mechanism for hand position detection is designed with specific aperture shapes and orientations optimized for detecting hand positions, while the illuminance detection mechanism uses different geometric configurations optimized for measuring light intensity. Each local detection system has customized optical properties matched to its measurement function.
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 configuration allows for highly reliable hand position detection by adjusting threshold settings based on illuminance conditions, minimizing the need for re-setting thresholds and ensuring accurate detection results without additional components.
Implementation Method 1
a first light detector and a second light detector that detect external light
Implementation Method 2
a first mechanism that limits an amount of the external light detected by the first light detector
Implementation Method 3
a second mechanism that limits an amount of the external light detected by the second light detector and has a different structure from a structure of the first mechanism
Data Source
Figure 1
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Figure 4~6
AI summary
Disclosed is an electronic timepiece (100) including: a second hand (3s), a minute hand (3m), and an hour hand (3h) that are driven to rotate around a shaft; and a first light detector (5) that detects external light and corresponds to one of the second hand (3s), the minute hand (3m), and the hour hand (3h); and a second light detector (6) that detects the external light, wherein the second light detector (6) is arranged on an outer side than a movement range of a tip of the hour hand (3h), or on outer side than a movement range of tails of the second hand (3s), the minute hand (3m), and the hour hand (3h).