Optical Rotary Operating Device for Wear-Free Phase Detection
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Solution Overview
Problem
Conventional rotary operating devices in electronic devices face issues such as wear particle-induced shorts, limited resolution adjustment, and increased device size due to fixed slit positions, which restricts the rotary operating member's rotation and requires complex pattern changes for different phase settings.
Innovation Solution
A rotary operating device with a reflective member featuring alternating bright and dark portions every 180 and 90 degrees, combined with a detection unit using photo reflectors to detect reflected light, allowing flexible resolution adjustment and compact design without wear-induced shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sliding contact between phase contact strip and conductive pattern is used, then phase detection is achieved, but wear particles cause unintended shorts and false detection
Solution Approach 1:
The patent replaces the mechanical sliding contact system with an optical detection system. A reflective member with reflection/non-reflection portions rotates with the operating member, and a light receiving unit detects the reflected light to determine rotation phase. This eliminates physical contact and wear particles entirely, resolving the contradiction between measurement precision and reliability.
2Measurement precision
If conductive pattern shape is changed for different phase numbers, then desired rotation angle resolution is achieved, but device complexity increases
Solution Approach 1:
Instead of changing the physical shape of conductive patterns for different phase numbers, the patent changes the detection parameters by configuring the reflective member with different numbers of reflection/non-reflection portions. The light receiving unit detects these optical patterns to achieve different rotation angle resolutions (e.g., 180-degree or 90-degree switching), simplifying the overall device structure while maintaining precision.
3Volume of moving object
If fixed slit positions are used in status detectable body, then device size is reduced, but rotary operating member cannot rotate all the way around
Solution Approach 1:
The patent makes the detection system dynamic by placing the light emitting unit and light receiving unit to detect reflected light from the rotating reflective member. As the reflective member rotates 360 degrees, the reflection/non-reflection portions dynamically pass by the detection units, enabling full rotation detection while maintaining a compact device size. The detection units remain stationary while the optical pattern rotates, achieving both compactness and full rotation capability.
4Measurement precision
If multiple photo-interrupters are used to detect 2n states, then detection resolution is improved, but device size increases
Solution Approach 1:
The patent makes the light emitting unit and light receiving unit serve multiple functions. By configuring the reflective member with different patterns of reflection/non-reflection portions, the same detection units can detect different numbers of phases (e.g., 2-phase, 4-phase, or higher resolutions). This multi-functionality achieves high detection resolution without increasing device size, as the detection hardware remains constant while the optical encoding varies.
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 stable phase detection with a clicking sensation, supports full 360-degree rotation, and allows for easy resolution change without increasing device size, while minimizing wear-related issues.
Implementation Method 1
a detection unit configured to detect reflected light from the reflective member
Data Source
AI summary
A rotary operating device includes a rotary operating member 20 that can rotate around a rotation axis, a reflecting plate 70 that can rotate integrally with the rotary operating member, and a detection unit 95 that detects reflected light from the reflecting plate 70. The reflecting plate 70 has a plurality of patterns as a detection target portion. A first pattern 70a1 is a circular portion that switches between a bright portion and a dark portion every 180 degrees around the rotation axis. A second pattern 70a2 is a circular portion that switches between a bright portion and a dark portion every 90 degrees around the rotation axis. An angle at which the first pattern 70a1 switches between the bright portion and the dark portion coincides with the angle at which the second pattern 70a2 switches between the bright portion and the dark portion.