Optical Tracking Bezel Rotation Detection for Smartwatches
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Solution Overview
Problem
Conventional electronic devices, such as smart watches, face challenges in accurately detecting the rotation of their bezels due to interference from outer magnetic fields and are prone to water and dust ingress.
Innovation Solution
The electronic device incorporates an optical tracking system (OTS) sensor and a rotational unit with a shaft and mating member, where the shaft passes through a thru-hole, and a waterproof member or translucent trough is used to prevent water and dust ingress, allowing the OTS sensor to detect the rotating angle without magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic sensor (e.g., Hall sensor) is used to detect the rotation of the bezel, then the rotation detection function is achieved, but the detection accuracy is reduced due to interference from outer magnetic fields
Solution Approach 1:
The patent replaces the magnetic sensor (electromagnetic detection system) with an optical tracking system (OTS) sensor that uses optical fields instead of magnetic fields to detect the rotating angle of the shaft. This substitution eliminates the vulnerability to magnetic field interference while maintaining the rotation detection function, directly resolving the technical contradiction between measurement precision and magnetic field interference susceptibility.
2Ease of operation
If the shaft passes through the case to enable rotation detection, then the rotational unit can be operated, but water and dust can enter the internal chamber through the thru-hole
Solution Approach 1:
The patent employs a waterproof member in the form of an O-ring seal that flexibly seals the gap between the shaft and the inner wall of the case defining the thru-hole. This flexible sealing mechanism allows the shaft to rotate freely while maintaining waterproof performance, preventing water and dust from entering the internal chamber through the thru-hole, thus resolving the contradiction between ease of operation and waterproof reliability.
3Reliability
If a waterproof member is added to seal the gap around the shaft, then waterproof performance is improved, but the device structure becomes more complex
Solution Approach 1:
The patent extracts the waterproof sealing function into a separate, dedicated component (the O-ring waterproof member) that is independently installed in the thru-hole. This extraction allows the sealing function to be implemented in a simple, standardized manner without complicating the overall device structure, as the waterproof member is a discrete element that can be easily installed and maintained, thus resolving the contradiction between improved waterproof performance and increased structural complexity.
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 solution effectively detects the rotating angle of the bezel without magnetic interference and prevents liquid or dust from entering the internal chamber, enhancing the accuracy and waterproofness of the device.
Implementation Method 1
The OTS sensor is arranged in the first chamber. The OTS sensor is corresponding in position to the first segment for detecting a rotating angle of the first segment.
Implementation Method 2
The waterproof member is configured to seal a gap between the second segment of the shaft and an inner wall of the case defining the thru-hole.
Data Source
AI summary
An electronic device includes a case, a manipulation ring disposed on the case, a rotational unit, a waterproof member, and an optical tracking system (OTS) sensor. The case has a first chamber and a second chamber arranged outside the first chamber. The case has a thru-hole arranged between the first and second chambers. The rotational unit includes a shaft and a mating member arranged in the second chamber and connected to the shaft. The shaft has a first segment arranged in the first chamber and a second segment arranged in the thru-hole. The manipulation ring is spinable to rotate the mating member and the shaft. The waterproof member is configured to seal a gap between the second segment and an inner wall of the case defining the thru-hole. The OTS sensor is arranged in the first chamber and is corresponding in position to the first segment.