Optical Navigation Circuit for Wearable Device Input
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Solution Overview
Problem
Existing electronic devices, such as hand-held devices and watches, face issues with contact point switch oxidation leading to loose connections and mechanical gear wear, resulting in reduced precision and functionality over time.
Innovation Solution
An electronic apparatus utilizing optical navigation technology to detect displacement of a movable structure's surface image, allowing for precise determination of user operations without relying on conductive contacts or mechanical gears, thereby avoiding oxidation and wear-related failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal dome contact point switch is used to detect button pressing, then the button function can be implemented, but the contact point oxidizes over time causing loose connections and reduced reliability
Solution Approach 1:
The patent replaces the mechanical contact point switch with an optical sensing system. A light source emits light toward the button surface, and a photodetector detects changes in reflected light intensity or patterns when the button is pressed. This optical detection method eliminates physical contact between sensing components and the button, preventing oxidation and mechanical wear, thereby significantly improving reliability and service life.
2Ease of operation
If mechanical gear wheels are used in a watch crown, then the crown can be controlled, but the gear wheels wear out over time causing low precision
Solution Approach 1:
The patent replaces mechanical gear wheels with an optical encoding system. The watch crown features an optical code pattern (such as reflective markers or absorptive patterns) that can be optically detected. A light source and photodetector array track the position and rotation of the crown by detecting the optical pattern, enabling precise measurement of rotational angle and direction without mechanical contact, thus maintaining high precision indefinitely.
Solution Approach 2:
The patent utilizes optical property changes (reflectivity or absorptivity patterns) on the watch crown surface to encode position information. Different regions of the crown have different optical characteristics that create a detectable pattern when illuminated. As the crown rotates, the changing optical pattern is detected by the photodetector, allowing precise determination of rotational position and movement without mechanical wear.
3Measurement precision
If an optical navigation circuit is implemented to detect surface image displacement, then high precision operation detection is achieved, but the device complexity increases
Solution Approach 1:
The patent designs the optical navigation circuit to serve multiple functions: detecting button presses, measuring watch crown rotation, and potentially other user interactions. The same light source and photodetector components are used across different sensing applications, reducing overall device complexity while maintaining high measurement precision through software-based pattern recognition and signal processing.
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
The optical navigation technology ensures high precision and reliability in user operation detection, even after long-term use, by capturing and analyzing the displacement of a structure's surface image, thus preventing loose contact and mechanical wear issues.
Implementation Method 1
The optical navigation circuit is configured to capture reflection of a light emitting to the structure to detect at least one displacement of the surface image
Data Source
AI summary
An electronic apparatus includes a structure and an optical navigation circuit. A first end of the structure is located inside the electronic apparatus and its second end corresponds to a user's control. The structure can be moved forward/backward in a specific direction and/or rotated in another direction. The optical navigation circuit captures reflection of a light emitting to the structure to detect displacement of the image along a specific axis of the structure, and determines the user's operating behavior as a specific operation according to a change of the sensed displacement of the image.