Shaft-Mounted Optical Encoder Detector Aperture Alignment
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Solution Overview
Problem
Conventional transmissive optical encoders are larger and more prone to misalignment compared to reflective encoders, leading to performance degradation due to the placement of the emitter and detector on opposite sides of the code wheel, which increases space consumption and complicates alignment.
Innovation Solution
A transmissive optical encoder design that includes a detector with an aperture for the rotary shaft, allowing for compact placement and easy alignment of the emitter and detector, utilizing a photosensor array on a substrate with a circular or rectangular shape to receive the modulated light signal, and a method for assembling the system that mounts the detector and code wheel directly on the motor shaft, facilitating efficient light signal modulation and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the emitter and detector are placed on opposite sides of the code wheel, then the transmissive optical encoder can function properly, but the device consumes more space and becomes more complex to align
Solution Approach 1:
The patent merges the emitter and detector into a single-sided configuration on the same side of the code wheel, eliminating the need for opposite-side placement. This is achieved by using a beam splitter to direct light from the emitter through the code wheel to the detector, reducing the overall encoder size while maintaining transmissive functionality
Solution Approach 2:
The patent introduces a beam splitter as an intermediary optical element that enables the emitter and detector to be positioned on the same side of the code wheel. The beam splitter divides and redirects the light path, allowing compact one-sided mounting while preserving the transmissive encoding mechanism
2Reliability
If the emitter and detector are placed on opposite sides of the code wheel, then the optical path is established, but misalignment occurs and performance degrades
Solution Approach 1:
By merging the emitter and detector positioning to the same side of the code wheel, the patent eliminates the alignment complexity between two separate components. The shared mounting base and proximity enable precise alignment through simpler mechanical means, reducing sensitivity to misalignment
Solution Approach 2:
The beam splitter serves as an intermediary that provides a fixed reference point for aligning the emitter and detector. By establishing the optical path through the beam splitter first, then aligning the code wheel to this established path, the system achieves high precision with reduced manufacturing 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
The solution results in a more compact optical encoder system with improved alignment capabilities, reducing space consumption and enhancing performance by allowing for precise positioning of the photosensor array relative to the code wheel, thus maintaining encoder resolution and accuracy.
Implementation Method 1
a stream of electrical signals is generated by a photosensor array that receives the modulated light
Data Source
AI summary
A transmissive optical encoder is disclosed. The transmissive optical encoder includes a detector, a code wheel, and an emitter. The detector includes an aperture through the detector. The aperture is configured to receive a rotary shaft of a motor. The code wheel is coupled to the rotary shaft of the motor. Rotation of the rotary shaft results in corresponding rotation of the code wheel. The emitter is configured to emit a light signal through the code wheel toward the detector. Rotation of the code wheel results in modulation of the light signal at the detector. Embodiments of the transmissive optical encoder consume relatively little space and facilitate alignment of the emitter and detector.